WO2021012048A1

WO2021012048A1 - Catalyst free, rapid cure silicone elastomers

Info

Publication number: WO2021012048A1
Application number: PCT/CA2020/051013
Authority: WO
Inventors: Michael A. Brook; Robert BUI
Original assignee: Mcmaster University
Priority date: 2019-07-22
Filing date: 2020-07-22
Publication date: 2021-01-28

Abstract

The present application provides a method for the rapid, catalyst-free, preparation of silicone elastomers using aminoalkylsilicones and aliphatic aldehydes that can dissolve in water at a concentration of at least 2 wt.%, in air or under water. The elastomers prepared by this method have good hydrolytic stability and can be used as hydrophobic adhesives or sealants under water.

Description

CATALYST FREE, RAPID CURE SILICONE ELASTOMERS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application Nos. 62/876,935, filed July 22, 2019, the contents of which are incorporated herein by reference in its entirety.

FIELD

[0002] The present application relates to the rapid, catalyst free, crosslinking in air or under water of silicone elastomers from polydimethylsiloxanes containing at least two amine groups, either telechelic or pendent functional, and aqueous solutions of aliphatic aldehydes to give silicone elastomers with tuneable physical properties.

BACKGROUND

[0003] Polysiloxane (silicone) elastomers possess many interesting properties including low toxicity, good thermal stability, hydrophobicity and high lubricity, etc.¹ These properties make silicones appealing in applications ranging from biomedical silicones, to cosmetics, coatings, and sealants. Typically, crosslinking of silicones into elastomers involves mixing silicone oil(s) in the presence of a catalyst to form the networked structure. The three most common methods of crosslinking silicone are hydrosilylation of alkene- modified silicones, room-temperature vulcanization (moisture cure of silanol-terminated silicones and functional silanes, RTV) and high temperature vulcanization (radical cure), as described in Brook,² which is incorporated by reference in its entirety. All of these methods of crosslinking are relatively slow and require a (metal) catalyst; quantities of catalysts or their residues generally remain in the material after cure. While small quantities of water may be advantageous (particularly for 1 - and 2- part RTV), these processes are generally intolerant of large quantities of water.

[0004] An alternative strategy for crosslinking silicones, without requiring a catalyst, exploits organic chemistry. There is a myriad of applicable organic functional groups that have been used to form organic crosslinks (azide-alkyne cycloaddition,³ boronic ester,⁴· ⁵ Diels-Alder,⁶ etc.). Amine-functionalized silicones are particularly attractive as starting materials because of their high reactivity, and the commercial availability of multiple molecular weights and degrees of functionality. Some examples of organic crosslinks formed from amine-modified silicones include aza-Michael reactions,⁷ ureas from reaction with isocyanates,⁸ and Schiff-bases through reaction with arylaldehydes.⁹ In the case of the latter two reactions, the elastomers form in minutes instead of hours, no catalyst is required, and water is the only by product. However, in these reactions too it is important to regulate the concentration of water during cure to prevent hydrolysis of the starting material or the resulting crosslinks.

[0005] Silicones are mostly insoluble in water; the solubility of the small cyclic silicone monomer D4 ((Me2SiO)4) in water is 56 parts per billion¹³). Larger silicone polymers are less soluble. While the incorporation of amine groups increases the water solubility, aminoalkylsilicones are essentially immiscible with water. Small aldehydes, including formaldehyde (commercial solution, typically 37% aldehyde/water), glyoxal (commercial solution, typically 40% aldehyde/water) and glutaraldehyde (8, 25, 50 or 70% aldehyde/water) are sold as concentrated solutions in water - these aldehydes are less soluble in polar and apolar organic solvents than aldehydes with higher molecular weight carbon chains.

[0006] The reaction between amines and formaldehyde, or related highly reactive aldehydes including glutaraldehyde and glyoxal, is extensively utilized in the characterization of biological entities and reaction products.¹⁰’ ¹¹ Historically, these processes were used as fixatives for proteins, including in embalming of cadavers, sterilization of biological entities, etc.¹² The key reaction is the generation of an imine base from the aldehyde and amine, and subsequent attack of another amine on the imine base to give an aminal (Figure 1 ).

SUMMARY

[0007] It has now been discovered that aqueous solutions or dispersions of reactive aldehydes react rapidly and efficiently with aminoalkylsilicones to form silicone elastomers. In some embodiments, the physical properties of the elastomers are controlled by the fraction of amine functional groups on the silicone polymer - at least one amine and one aldehyde are required for crosslink to form. In further embodiments, the rapid curing occurs readily in air and under water, to give elastomers that can be used, for example, as sealants. Removal of residual aldehyde, where necessary, can be induced by the addition of other amines to form less toxic products; such amines may include ethanolamine and alkylamines, including the aminosilicone polymer when amine groups are present in stoichiometric excess. [0008] The present application therefore includes a process for preparing silicone elastomers comprising combining

(i) a compound of the Formula (I), (II) or (III):

wherein

R¹- R²⁰ are independently selected from Ci-ioalkyl, C2-ioalkenyl, C2-ioalkynyl, C6-20

R22

I

Si s

R²¹ o- aryl, ^R" and linear and branched siloxanes (R²¹- R²³ are independently selected from Ci-ioalkyl, C2-ioalkenyl, C2-ioalkynyl, C6-2oaryl, and linear and branched siloxanes);

n is 0-2000 (or 0-1000), if n=0, m = 2-60, if n>10, then m = 1-60% of n, with m being at least 2;

q is 0-2000, if q = 0, r = 2-60, if q > 10, then r = 1 -60% of q, with r being at least 2; p is 0-2000;

and

Y is an amino-modified group, in which the amine is a primary or secondary amine connected to the silicone polymer through a linker R²⁴, wherein the linker R²⁴ is selected from Ci-ioalkyl, Ci-ioalkylene, C2-ioalkenyl, C2-ioalkenylene, C2-ioalkynyl, C2-ioalkynylene, C6-2oaryl, or C6-2oarylalkyl, and wherein the nitrogen atom(s) of the primary or secondary amine is connected to the linker via a sp³ hybridized carbon, and wherein one or more carbons of R¹⁸ may be substituted with O, NH, NR or S groups;

with

(ii) a reactive aldehyde that has the capacity to react with an amine to form a covalent bond via an imine or aminal linkage (see for example, Figure 2).

[0009] In one embodiment, the reactive aldehyde is an aqueous solution or dispersion and crosslinks the compounds of formula (I), (II) or (III) to form the silicone elastomers.

[0010] The present application also includes a method for the dispensing of pre elastomer materials (compounds of the Formula (I), (II) or (III), and a reactive aldehyde) through a mixhead directly on the locus of reaction in air or in water, where the elastomer forms in situ (Figure 3), for example, as a sealant, or an adhesive (Figure 4).

[001 1] Other features and advantages of the present application will become apparent from the following detailed description. However, it should be understood that the detailed description and the specific examples, while indicating embodiments of the application, are given by way of illustration only and the scope of the claims should not be limited by these embodiments, but should be given the broadest interpretation consistent with the description as a whole.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the application will now be described in greater detail with reference to the attached drawings in which:

[0012] Figure 1 shows fixation reactions between reactive aldehydes and amines.

[0013] Figure 2 shows putative reactions between an aminoalkylsilicone and A: glutaraldehyde, B: glyoxal, and C: formaldehyde in some embodiments of the disclosure.

[0014] Figures 3A-E are photos which show an elastomer of the disclosure as a sealant under water and Figure 3F shows an elastomer of the disclosure. A: Five holes cut into polyethylene container (picture taken from above): B: water leaking from the container. C: Application of sealant derived from DMS-A1 1 and formaldehyde solution, respectively, in a double barrel syringe with mixing tip through the water over about 10 s. D: Non-leaking device 16 s after start of application. E: An overhead view of Figure (A-D), F: The same mixture was used to print elastomeric letters in air; gel time was 12 s. [0015] Figure 4 are graphs which show stress-strain from adhesive forces of elastomers of the disclosure cured onto the surface of various materials.

[0016] Figure 5 is a graph for determining the crosslinking stoichiometry of telechelic aminopropylPDMS (molecular weight 25,000 g mol ¹) using formaldehyde, glutaraldehyde, and glyoxal in certain embodiments of the disclosure.

[0017] Figure 6 are graphs showing the oscillatory rheology of elastomers of the disclosure to compare the gelation point (intercept of G’ and G”) from the reaction of A: Formaldehyde, B: Glyoxal and C: Glutaraldehyde, with neat DMS-A15 and a 50% emulsion with water.

[0018] Figure 7 is a graph showing the cure times for elastomers of the disclosure determined by a change in Young’s modulus for DMS-A15 cured with formaldehyde, glutaraldehyde, and glyoxal.

[0019] DETAILED DESCRIPTION OF THE APPLICATION

(i) Glossary

[0020] Unless otherwise indicated, the definitions and embodiments described in this and other sections are intended to be applicable to all embodiments and aspects of the present application herein described for which they are suitable as would be understood by a person skilled in the art.

[0021] The present application refers to a number of chemical terms and abbreviations used by those skilled in the art. Nevertheless, definitions of selected terms are provided for clarity and consistency.

[0022] As used herein, the words“comprising” (and any form of comprising, such as“comprise” and“comprises”),“having” (and any form of having, such as“have” and “has”), “including” (and any form of including, such as “include” and “includes”) or “containing” (and any form of containing, such as“contain” and“contains”), are inclusive or open-ended and do not exclude additional, unrecited elements or process/method steps.

[0023] As used herein, the word“consisting” and its derivatives, are intended to be close ended terms that specify the presence of stated features, elements, components, groups, integers, and/or steps, and also exclude the presence of other unstated features, elements, components, groups, integers and/or steps. [0024] The term“consisting essentially of”, as used herein, is intended to specify the presence of the stated features, elements, components, groups, integers, and/or steps as well as those that do not materially affect the basic and novel characteristic(s) of these features, elements, components, groups, integers, and/or steps.

[0025] Terms of degree such as“substantially”,“about” and“approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of at least ±5% of the modified term if this deviation would not negate the meaning of the word it modifies.

[0026] As used in this application, the singular forms“a”,“an” and“the” include plural references unless the content clearly dictates otherwise. For example, an embodiment including“a compound” should be understood to present certain aspects with one compound or two or more compounds. In embodiments comprising an “additional” or“second” component, such as an additional or second compound, the second component as used herein is chemically different from the other components or first component. A “third” component is different from the other, first, and second components, and further enumerated or“additional” components are similarly different.

[0027] The term“and/or” as used herein means that the listed items are present, or used, individually or in combination. In effect, this term means that“at least one of” or “one or more” of the listed items is used or present.

[0028] The term “alkyl” as used herein, whether it is used alone or as part of another group, means straight or branched chain, saturated alkyl groups. The number of carbon atoms that are possible in the referenced alkyl group are indicated by the prefix “Cni-n2”. For example, the term C1 -1 Oalkyl means an alkyl group having 1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms.

[0029] The term“alkenyl” as used herein, whether it is used alone or as part of another group, means straight or branched chain, unsaturated alkyl groups containing at least one double bond. The number of carbon atoms that are possible in the referenced alkylene group are indicated by the prefix“CniV. For example, the term C2-10alkenyl means an alkenyl group having 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms and at least one double bond. In the case of aminoalkenyl compounds, the N shall be bonded to the linker via an sp3 hybridized carbon. [0030] The term“alkynyl” as used herein, whether it is used alone or as part of another group, means straight or branched chain, unsaturated alkyl groups containing at least one triple bond. The number of carbon atoms that are possible in the referenced alkylene group are indicated by the prefix“CniV. For example, the term C2-10alkynyl means an alkynyl group having 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms and at least one triple bond. In the case of aminoalkynyl compounds, the N shall be bonded to the linker via an sp3 hybridized carbon.

[0031 ] The term“aryl” as used herein, whether it is used alone or as part of another group, refers to cyclic groups containing from 6 to 20 carbon atoms and at least one aromatic ring. In an embodiment of the application, the aryl group contains from 6, 9 or 10 carbon atoms, such as phenyl, indanyl or naphthyl.

[0032] The suffix“ene” as used herein, for example in“alkylene”, “alkenylene” means divalent hydrocarbon radicals having straight, branched or cyclic moieties or combinations thereof.

[0033] The term "hydrocarbyl" as used herein refers to a group comprising at least C and H that may optionally comprise one or more other suitable substituents.

[0034] The term monomer is used to describe a silane or siloxane moiety that is possible of undergoing reactions to give siloxane products of increased molecular weight.

[0035] The term oligomer is used to describe a siloxane moiety that is prepared by reactions of lower molecular weight siloxanes or silanes (monomers). The number of monomers contained in an oligomer is <20.

The term“linear siloxane” as used herein refers to a group comprising

units, wherein R, R', R" and R'" are independently selected from Ci-ioalkyl, C2-ioalkenyl, C2-10alkynyl and, arranged in linear fashion. The number of units may be

R

R""— Si-1- between 1 and 10 with the terminal group being R' , wherein R"" is selected from Ci-ioalkyl, C2-ioalkenyl, C2-ioalkynyl and C6-2oaryl. [0037] The term“branched siloxane” as used herein refers to a group comprising R R"

s I I _t

- -Si-O-Si—-

R' R'" units, wherein R, R', R" and R'" are as defined above, with the exception that

R

O-Si-jl·

I ¹

at least one of R, R', R" and R'" is R' . The number of units may be between 1 and 10

R

R""— Si-f- i ^<

with any terminal group being R' , wherein R"" is selected from Ci-ioalkyl, C2- ioalkenyl, C2-ioalkynyl and aryl.

[0038] The term“imine” as used herein refers to a C=N double bond arising from the reaction of a reactive aldehyde and an aliphatic amine, which may include aminoalkylsilicones.

[0039] The term“aminal” as used herein refers to a N-C-N linkage arising for reaction of a reactive aldehyde and two equivalents of an aliphatic amine, which may include aminoalkylsilicones.

[0040] The term“aminoalkylsilicone” as used herein refers to a linear or branched silicone polymer containing at least 2 amino groups in which at least 1 aliphatic or aromatic carbon atom is present between the silicon and nitrogen atoms and refers to a primary or secondary amine connected to the silicone polymer through a linker R²².

[0041] The term“reactive aldehyde” as used herein refers to an aldehyde with sufficient solubility in water (or is able to form a dispersion) and is able to react rapidly with the aminoalkylsilicones of the formula (I), (II) or (III) to form crosslinks and form the elastomers of the disclosure. In certain embodiments, the reactive aldehyde is for example, formaldehyde, glyoxal and other aliphatic aldehydes that can dissolve in water at a concentration of at least 2wt%.

(ii) Processes for preparing elastomers

[0042] The present disclosure includes a process for preparing silicone elastomers comprising combining

(i) a compound of Formula (I), (II) or (III):

wherein

R¹- R²⁰ are independently selected from Ci-ioalkyl, C2-ioalkenyl, C2-ioalkynyl, C6-

R²²

I

Sk ¾

R^{21 1} "0-f-

2oaryl, ^R and linear and branched siloxanes (R²¹- R²³ are independently selected from Ci-ioalkyl, C2-ioalkenyl, C2-ioalkynyl, aryl, and linear and branched siloxanes);

Y is an amino-modified group, in which the amine is a primary or secondary amine connected to the silicone polymer through a linker R²⁴, wherein the linker R²⁴ is selected from Ci-ioalkyl, Ci-ioalkylene, C2-ioalkenyl, C2-ioalkenylene, C2-ioalkynyl, C2-ioalkynylene, C6-2oaryl, or C6-2oarylalkyl, and wherein the nitrogen atom(s) of the primary or secondary amine is connected to the linker via a sp³ hybridized carbon, and wherein one or more carbons of R²⁴ may be substituted with O, NH, NR or S groups;

with

(ii) a reactive aldehyde that reacts with an amine to form a covalent bond via an imine or aminal linkage. [0043] In another embodiment, the reactive aldehyde is in an aqueous solution or aqueous dispersion, and the aqueous solution or dispersion is combined with the compound of formula (I), (II) or (III).

[0044] In another embodiment, the compound of the formula (I), (II) or (III) is combined with water, which mixture is then combined with the reactive aldehyde. In another embodiment, the reactive aldehyde is neat or in an aqueous solution or dispersion.

[0045] In one embodiment, the moieties

are randomly distributed throughout the compounds of formula (I) or (III) and the integers ‘n’,‘m’,‘q’ and Ύ represent the overall number of moieties throughout the compound. In one embodiment, n is 1-1000 and m is 2-60, and where n is 0, m is 2-60, and wherein if n>10, then m = 1-60% of n, but m must be at least 2. In one embodiment, n is 0-1000 and where n is 0-10, m is 2-60, and where n>10, then m = 1-60% of n, but m must be at least 2. In another embodiment, the moieties are formed from block copolymers.

[0046] In another embodiment, n is 0-2000 (or 0-1000), if n=0, m = 2-60, if n>10, then m = 1 -60% of n_; q is 0-2000 (or 0-1000), r = 0-150 and if q = 0, r = 1 -50; p is 0-2000 (or 0-1000).

[0047] In one embodiment, n is 0-2000, if n=0, m = 2-60, if n>10, then m = 1 -60% of n. In another embodiment, n is about 0-2000, or about 10-2000, or about 10-1000, or about 50-1000, or about 100-1000. In one embodiment, m is 2-60, or 3-60, or 2-40, or 2- 20, or 2-10.

[0048] In another embodiment, q is about 0-2000, or about 10-2000, or about 10- 1000, or about 50-1000, or about 100-1000. In one embodiment, r is 0-60, or 2-60, or 3- 60, or 2-40, or 2-20, or 2-10.

[0049] In another embodiment, p is about 0-2000, or about 10-2000, or about 10- 1000, or about 50-1000, or about 100-1000. [0050] In one embodiment, R¹-R²⁰ are independently or simultaneously selected

R22

I

SL I

R^{21 1} _2gO-¾- from Ci-6alkyl, C2-6alkenyl, C2-6alkynyl, C6-ioaryl, ^R and linear and branched siloxanes.

[0051] In one embodiment, R¹-R²⁰ are independently or simultaneously selected

R22

I

Si.

R²¹ I "o-f- from Ci-6alkyl, C2-6alkenyl, C2-6alkynyl, C6-ioaryl, ^R and linear and branched siloxanes.

[0052] In one embodiment, R¹-R²⁰ are independently or simultaneously selected from Ci-3alkyl or phenyl. In one embodiment, R¹-R²⁰ are Chta.

[0053] In one embodiment, R² is Y.

[0054] In another embodiment, R²¹-R²³ are independently or simultaneously selected from Ci ealkyl, C2-6alkenyl, C2-6alkynyl and C6-ioaryl. In another embodiment, R²¹ -R²³ are independently or simultaneously selected from Ci salkyl or phenyl. In one embodiment, R²¹-R²³ are Chb.

[0055] In another embodiment, Y is an amino-modified group having one or more amine groups, in which the amine is a primary or secondary amine connected to the silicone polymer through a linker R²⁴, wherein the linker R²⁴ is selected from Ci-ioalkyl, Ci-ioalkylene, C2-ioalkenyl, C2-ioalkenylene, C2-ioalkynyl, C2-ioalkynylene, C6-2oaryl, or C6- 2oarylalkyl, and wherein the nitrogen atom(s) of the primary or secondary amine is connected to the linker via a sp³ hybridized carbon, and wherein one or more carbons in R²⁴ may be replaced with one or more nitrogen atoms (NH or N-(Ci-6alkyl)) or sulfur atoms. In another embodiment, Y is -R²⁴NH2 or -R²⁴-NHR^a, wherein R^a is Ci ealkyl optionally substituted with amino (Nhte). In another embodiment, R²⁴ is selected from Ci- ealkyl, Ci-6alkylene, C2-6alkenyl, C2-6alkenylene, C2-6alkynyl, C2-6alkynylene, C6-ioaryl, or C6-ioarylalkyl. In another embodiment, R²⁴ is selected from Ci ealkyl, or Ci-6alkylene, wherein one or more of the carbon atom is replaced with one or more nitrogen or sulfur atoms.

[0056] In one embodiment, Y is -R²⁴-NH2 or -R²⁴-(NH2)2 and for example 'O'NH_j,

[0057] In one embodiment, compound of formula (I), (II), or (III) is selected from

wherein s, t = 0-1000 and u=1 , v= 0; or v = 2-225 and u = at least 1 and up to 12% v.

[0058] In another embodiment, the compound of formula (II) is

[0059]

, wherein t is an integer that ranges from 20 to

1000.

[0060] In another embodiment, the reactive aldehyde is formaldehyde.

[0061 ] In another embodiment, the reactive aldehyde is a dialdehyde, tri-aldehyde (or higher) and is of the formula W-[(C=0)H]b, wherein W is a Ci-i2hydrocarbyl radical and b is an integer 2 or higher (e.g. 2, 3, 4, 5, 6). In one embodiment, the "hydrocarbyl" as comprises at least C and H that may optionally comprise one or more other suitable substituents. In one embodiment, the hydrocarbyl radical is a linear or branched Ci- i2alkylene, substituted terminally at each branch with a reactive aldehyde. In one embodiment, the reactive aldehyde is oligo(acrolein).

[0062] In another embodiment, the reactive aldehyde is of the formula H(C=0)-X- (C=0)H, wherein X is Ci-i2alkylene, Ci-ioalkylene, Ci-6alkylene. In another embodiment, the reactive aldehyde is glutaraldehyde, glyoxal, succinaldehyde (butanedial) or adipaldehyde (hexanedial).

[0063] In an embodiment, the combination of an aminoalkylsilicone with an aqueous solution or dispersion of a reactive aldehyde leads to a crosslinked silicone elastomer. Particularly convenient examples of aminoalkylsilicones include: telechelic, and pendant aminopropylsilicones Formula IV, and V, where a, b, c and d are integers; c and d 0-1000, if c=0, a+b = 2-60, if c>10, then a+b = 1 -60% of c.

[0064] In an embodiment, it is possible to modify all or only some of the available amine groups. For example, both Formula VI and VII can be elastomeric; harder elastomers are observed with increasing numbers of aminal crosslinks compared to the total number of silicone monomer units.

[0065] In an embodiment, rate of cure was moderated by dilution with volatile alcohols, or lower alkyl alcohols, such as isopropanol.

[0066] In an embodiment, the physical properties of the elastomer are tuned by use of substoichiometric (less than 1 ) quantities of reactive aldehydes. [0067] In one embodiment, the physical properties of the elastomer is controlled by manipulation of the ratio of Nhte and CHO functional groups. In another embodiment, the ratio of [NH2]/[CHO] functional groups is 0.5-2 for formaldehyde-derived elastomers and 1-3 for glyoxal-derived elastomers.

[0068] The present application also includes a method for the dispensing of pre elastomer materials through a mixhead directly on the locus of reaction in air or in water, where the elastomer forms in situ, for example, as a sealant.

[0069] In a further embodiment, the resulting elastomers are able to adhere to a variety of substrates, including poly(methyl methacrylate), polystyrene, glass and Teflon (Figure 4).

[0070] In an additional embodiment, the product elastomers do not undergo loss of crosslinking (i.e reversal of crosslinking); small decreases in modulus are observed in ‘wet’ samples (that have absorbed water), which recover to the original strength after drying in air.

[0071] In another embodiment, aminoalkylsilicones, such as those of the formula (I), (II) or (III) are generally hydrophobic, repel water and do not dissolve in water. In a further embodiment, the reactive aldehydes are either soluble in water to form aqueous solutions, or solubilize to an appreciable extent to form dispersions, and surprisingly rapidly react and crosslink with the aminoalkylsilicones of the disclosure to form the elastomers. In one embodiment, the elastomers of the disclosure are able to cure underwater.

[0072] The present disclosure also includes elastomers formed from aminoalkylsilicones crosslinked with reactive aldehydes. Accordingly, in one embodiment, the present disclosure includes elastomers comprising:

(i) a compound of Formula (I), (II) or (III):

wherein

R22

I

Sl· I

R^{21 1} ₂₃0-f-

n is 0-2000, if n=0, m = 2-60, if n>10, then m = 1-60% of n;

q is 0-2000, if q=0, r = 2-60, if q>10, then r = 1-60% of q;

p is 0-2000;

wherein the compound of formula (I), (II), or (III) is crosslinked with a reactive aldehyde,

wherein all of the variables are further defined as in the processes above.

[0073] In some embodiments, the elastomers of the present disclosure surprisingly demonstrate high hydrolytic stability even though imine and aminal bonds can be reversible in the presence of water. In some embodiments, the elastomers of the disclosure are stable under water or in the presence of water. In another embodiment, the elastomers of the disclosure demonstrate less than a 10% (0-10%), or less than 5% (0-5%) reduction in the Young’s modulus of the elastomer after being submerged in water for 24 hours.

[0074] The following non-limiting examples are illustrative of the present application. As is apparent to those skilled in the art, many of the details of the examples may be changed while still practicing the methods, compositions and kits described herein.

EXAMPLES

Materials

[0075] 3-(Aminopropyl)methylsiloxane-dimethylsiloxane copolymers: AMS-132 (2- 3% mol aminopropylmethylsiloxane, 4500-6000 g mol ¹), AMS-152 (4-5% mol aminopropylmethylsiloxane, 7000-9000 g mol ¹), AMS-162 (6-7% mol aminopropylmethylsiloxane, 4000-5000 g mol ¹), AMS-191 (9-1 1 % mol aminopropylmethylsiloxane, 2000-3000 g mol ¹), AMS-1203 (20-25% mol aminopropylmethylsiloxane, 20000 g mol ¹); and telechelic 3-(aminopropyl)-terminated polydimethylsiloxanes: DMS-A1 1 (850-900 g mol ¹), DMS-A12 (900-1000 g mol ¹), DMS- A15 (3000 g mo ), DMS-A21 (5000 g mo ), DMS-A31 (25000 g mol ¹), DMS-A35 (50000 g mol ¹), aminoethylaminopropyl-methylsilooxanedimethylsiloxane copolymer; AMS-233 (2-4% mol aminoethylaminopropylmethylsiloxane) were purchased from Gelest. The formalin solution (37% wt. formaldehyde in water) was purchased from VWR. Glyoxal solution (40% wt. in water) was obtained from Sigma-Aldrich. All reagents were used without further purification.

Methods

[0076] Elastomers destined for tensile testing were cured in a Teflon dog bone- mold (30 mm x 10 mm x 5 mm with 5 mm inner central width), or a Pyrex glass 9-well spot plate (22.2 mm x 7 mm wells) or a polypropylene flat-bottom 12-well plate for mechanical testing. For 2-part mixing applications, 10 mL dual-barrel syringes equipped with a 74 mm 1 :1 or 10:1 ratio mixing nozzle (16 mixing elements) were purchased from McMaster-Carr.

[0077] Infrared spectroscopy was conducted using a Thermo Scientific Nicolet 6700 FT-IR spectrometer equipped with a Smart iTX attenuated total reflectance (ATR) attachment. NMR spectra (at 600 Hz for ¹H) were obtained using a Bruker Avance 600 spectrometer. Thermal stability was determined using a TGA Q50 thermogravimetric analyzer (TA Instruments) under an argon atmosphere.

[0078] A Shore OO durometer (Rex Gauge Company, Inc. U.S.) was used to characterize the hardness of the elastomer. Young’s moduli were measured using a MACH-1 micromechanical testing instrument (Biomomentum Instruments) equipped with a 0.5 mm hemispherical indenter using a Poisson ratio of 0.3 and a constant indentation depth of 1.0 mm; all measurements were conducted at 22 °C and in triplicate. Tensile strength experiments were performed on an Instron 5900 series Universal Mechanical Tester (ITW company) equipped with a 50 N load cell, all experiments were conducted at a constant rate of 5 mm min ¹. Rheology measurements were conducted on a TA Instruments HR-2 Rheometer with 40 mm parallel plate geometry and Peltier plate set to a 500 pm gap at 25 °C.

[0079] Simply mixing neat aminoalkylsilicones with an aqueous solution of reactive aldehyde immediately leads to an increase in viscosity and then formation of an elastomer; there is typically an accompanying color change to yellow and in some cases orange or brown. In the case of formaldehyde, gelation to form a self-supporting elastomer in air took < 30 s; glyoxal reacted somewhat more slowly. Under water, cure with formaldehyde took 16 s. Without wishing to be constrained by theory, both reactions to form an imine with formaldehyde, and the subsequent attack by amine on the Mannich imine, will occur during crosslinking and are rapid. In the case of glyoxal, an analogous first step will occur, while the second step is slower and therefore results in a longer gelation time. If insufficient amine is provided to react with the glyoxal, the Mannich imine decomposes back to the starting amine and aldehyde. Using glutaraldehyde as the curing agent the initial steps are similar to glyoxal, but the aldehydes can additionally polymerize by aldol autocondensation as an additional type of crosslinking process. (Figure 1 , Figure 2)

[0080] The physical properties of the elastomer formed are controlled by the crosslink density. When all available amines participate in crosslinking (sufficient aldehyde is present to react with all amines), the crosslink density is affected by amine spacing along the silicone backbone and the facility with which internal reactions (loops) form. Lower crosslink densities also accompany the addition of lower than stoichiometric values (1 aldehyde can consume up to 2 amines). Thus, for a given, pendant aminoalkylsilicone, the crosslink density is tuned simply by the quantity of aldehyde added.

Synthesis of Aldehyde Crosslinked Elastomers

[0081] Form-PDMS (Formaldehyde-Crosslinked Pendant-AminopropylPDMS Elastomers) were prepared using 3-(aminopropyl)methylsiloxane-dimethylsiloxane copolymers (@ 3, 5, 7, 10 % mol 3-(aminopropyl)methylsiloxane, respectively) at room temperature (Table 1 ). In a typical preparation, formalin solution (25.0 mI_, 37wt% formaldehyde in water, 0.345 mmol H2CO) was added to a vial containing AMS-152 (0.955 g, 5% mol aminopropylmethylsiloxane 8500 g mol ¹, 0.645 mmol NH2) and stirred until the solution turned homogenous and opaque (~ 3 s). The mixture gelled rapidly (<30 s) into a soft white elastomer. The opacity slowly decreased as water physically separated by moving from the interior to the external surface of the elastomer body. The elastomer was allowed to cure for 3 h at room temperature before being placed in a 45 °C vacuum oven at 0.3 torr for 3 h to further dehydrate the sample leaving a clear transparent elastomer. Physical tests on the elastomer were conducted after the latter dehydration step. (0.970 g, 98.6% recovered yield). Samples of the elastomer were ground into small pieces and swollen with solvent to obtain the NMR results.

[0082] ¹ H NMR (600 MHz, chloroform-d) d 0.050 (s, Si-CHs), 0.45 (t, 2H, S1-CH2, J = 8.64 Hz), 1 .40 (p, 2H, CH₂, J = 8.60 Hz), 2.59 (q, 2H, CH₂, J = 7.1 1 Hz), 3.30 (s, 2H, HNCH2NH). IR (ATR-IR, cm ¹): 2962, 2905, 1445, 141 1 , 1257, 1008, 862, 784, 698, 685, 661 , 619, 605, 568, 560.

[0083] Alternatively, Form-PDMS elastomers can be prepared using telechelic 3- (aminopropyl)-terminated polydimethylsiloxanes (@ 900, 3000, 5000, 25000, 50000 g mol ¹) with formaldehyde in a 1 :1 amine to aldehyde ratio and longer reaction times (Table 1 ). For example, formalin solution (25.0 mI_, 37wt% formaldehyde in water, 0.345 mmol H2CO) was added to a vial containing DMS-A21 (0.910 g, 5000 g mol ¹ telechelic aminopropyl-terminated PDMS, 0.364 mmol NH2) and stirred the mixture until homogenously opaque (~3 s). This mixture gradually crosslinked until gelled after 10 mins. Crosslinking was completed after 1 hour at room temperature to obtain a white opaque elastomer. After slowly drying in a 45 °C vacuum oven at 0.3 torr for 12 h the elastomer turned transparent. [0084] The efficiency of cure, as a function of aldehyde/amine ratio was determined for each crosslinker (formaldehyde, glutaraldehyde, and glyoxal) by adding different ratios of HCHO to telechelic aminopropylPDMS DMS-A31 (30,000 g mol ¹). The [Amine]/[Aldehyde] ratio that produced the maximal elastomer strength was determined to be the optimal reaction stoichiometry (Figure 5).

[0085] Cure when using silicones with higher amine concentrations (e.g., DMS- A1 1 850-900 g mol ¹ or AMS-1203 20-25% mol aminopropylmethylsiloxane, 20000 g mol ¹) was extremely rapid, impractically so in some cases. It was found that the addition of addition of isopropanol (a Ci-6alcohol) could extend pot life. For example, formalin (88 mI_, 37 % wt. formaldehyde in water, 1 .12 mmol) was first combined with 30 mI_ of isopropanol. This solution was added to a vial containing DMS-A1 1 (0.950 g, 2.23 mmol NH2) and quickly stirred until homogenous (~ 3 s). The elastomer was allowed to cure for 24 h at room temperature to allow the isopropanol to evaporate slowly, followed by the dehydration step at 45 °C described above.

[0086] Silicone pre-elastomers could conveniently be dispensed from a double barrel syringe, where the 2 barrels are connected by a static mixing head. Various concentrations of amine and aldehyde were used for 2-part mixing syringe experiments. For example, the hardest formaldehyde elastomer was printed with a slight excess of aldehyde using a 10: 1 dual barrel syringe equipped with a mixing nozzle. The larger barrel was loaded with 7 ml_ of DMS-A1 1 (6.55 g, 7.70 mmol) and the smaller barrel was loaded with 0.7 ml_ of formalin solution (0.756 g, 9.32 mmol H2CO). The mixture was extruded from the dual syringe as a homogenous white gel that cured into an opaque white elastomer over 12 s. Using this dual syringe method, the word‘Chemistry’ was spelled out using the elastomer (Figure 3E). The letter rapidly gelled upon extrusion (10 s) giving 0.3 cm thick letters.

Strain

% mol Mn ₁ Shore

, [Amine] . . Young’s Stress at at amino- (g ^L, , , L hardness

modulus (MPa) break (MPa) break propyl mol ') <^m°' ^L > (00)

(%)

Telechelic-modified aminopropylsilicones and Formaldehyde (For-T)

900 2.30 75 1.40 ±0.01 0.32±0.03 105

3000 0.653 64 0.880±0.02 0.18±0.01 133

5000 0.392 57 0.661 ±0.002 0.10±0.02 187 25000 0.0784 38 0.0461 ±0.001 0.088±0.004 205

50000 0.0392 22 0.0205±0.003 0.065±0.002 224

Pendent-modified aminopropylsihcones and Formaldehyde (For-P)

3% 5500 0.258 12 0.0896±0.0004 0.012±0.01 185

5% 8000 0.675 46 0.688±0.001 0.37±0.01 130

7% 4000 0.946 57 0.759±0.003 0.42±0.01 1 15

10% 2500 1.35 75 1.26±0.02 0.66±0.01 1 10

25% 2000 3.38 12 (A) 1.73±0.03 0.95±0.01 105

Table 1 : Preparation of silicone elastomers using formaldehyde.

[0087] Excess formaldehyde was removed from the elastomer by evaporation after curing and in the vacuum oven. Aldehyde groups that remain in the elastomer after evaporation can be removed by soaking the elastomer in a solution containing a relatively benign monofunctional amine such as lysine or aminoethanol. These amines react with the excess aldehydes in solution. The hydrophobicity of the silicone elastomer prevents swelling by water so, aqueous solution may only react with excess aldehydes on the surface of thee elastomer. Using a solvent with better compatibility with silicones such as isopropanol as aids swelling.

Curing Under water

[0088] The high reactivity of aldehydes towards amines allows for cure to occur even in the presence of excess water. For example, 5m L of DMS-A15 (4.85 g, 1.62 mmol) was combined with 5 ml_ of distilled water in a vial and stirred until emulsified into a cloudy white liquid. To this mixture, 0.5 ml_ of formalin solution (0.540 g, 6.66 mmol H2CO) was added and the vial was shaken for 3 s. After <15 s the mixture quickly gelled into a solid white elastomer.

[0089] Water was expected to disrupt the cure of FORM-PDMS because it is eliminated as a byproduct in the first step of both reactions; forming the imine. By contrast, the formaldehyde-crosslinked elastomers displayed remarkable resilience to water during and after full cure. Oscillatory rheology was used to probe the sol-to-gel transition of the silicone emulsified in water and then compared to a neat mixture of the silicone oils using rheological studies. AminopropylPDMS with the low amine concentrations (DMS-15) were selected because they exhibit slow cure times such that the cure could be measured in the time scale of rheology (>2.5 s); higher concentrations led to cure before oscillations begin. 2% pendent-aminopropylPDMS was emulsified without surfactant in a 1 : 1 mixture with water, then combined with formaldehyde such that [amine]o=[aldehydes]o.The presence of water significantly increased the gelation time (interception of G’ and G” values, Figure 6) of the material; the gelation time for a formaldehyde crosslinked elastomer increased from 13 s to 51 s. The modulus at gelation for silicone-water emulsions was higher than for neat samples. The emulsified samples had virtually the same Young’s modulus and Shore hardness as samples prepared neat after complete cure (5 h) for FORM-PDMS. These experiments were repeated for glutaraldehyde and glyoxal with similar results (Figure 6).

[0090] Glyox-PDMS (Glyoxal-Crosslinked Pendant- and Telechelic- AminopropylPDMS Elastomers; analogous procedures may be used for glutaraldehyde - Glu-PDMS) were prepared using 3-(aminopropyl)methylsiloxane-dimethylsiloxane copolymers (@ 3, 5, 7, 10 % mol 3-(aminopropyl)methylsiloxane, respectively) or using telechelic 3-(aminopropyl)-terminated polydimethylsiloxanes (@ 900, 3000, 5000, 25000, 50000 g mol ¹) a 2:1 ratio of NFte: aldehyde (Table 2). For example, AMS-152 (0.923 g, 5% mol aminopropylmethylsiloxane 8500 g mol ¹, 0.624 mmol NH2) was combined with glyoxal solution (17.7 mI_, 40%wt glyoxal in water, 0.156 mmol, 0.312 mmol H2CO) in a vial and stirred until homogenous white opaque then poured into a glass spot plate. The mixture slowly increases in viscosity until it gelled (60 s) into a pale yellow elastomer. The elastomer was allowed to cure for 12 h at room temperature. The elastomer turned from pale yellow to light red after complete curing. The elastomer was then placed in a 60 °C oven for 18h before mechanical testing. The infrared and NMR spectra (Figure 8B and C) of the material was also obtained.

[0091] Glyox-PDMS IR (ATR-IR): v = 3005, 2962, 2905, 1670, 1446, 1412, 1274, 1257, 1077, 1009, 863, 785, 750, 661 , 633 cm-¹. Glu-PDMS IR (ATR-IR): v = 3085, 3027, 2961 , 1654, 1523, 1495, 1459, 1379, 1260, 1081 , 1029, 1016, 803, 725, 693, 655 cm ¹.

[0092] The cure time using optimal stoichiometry for each crosslinker was determined by measuring the Young’s modulus of DMS-A15 (3000 g mol ¹ telechelic aminopropylPDMS), as a function time from when the crosslinker is added. The time at which the maximal elastomer strength was observed is the cure time (Figure 7). Table 2: Preparation of silicone elastomers using glutaraldehyde and glyoxal

Stress

% mol Mn [Amine] Young’s Strain at at break

aminopropyl (gmol^-1) (mol L·¹) (oo)^{neSS m}°dulus (MPa) break (%)

(MPa)

Telechelic-Modified AminopropylPDMS and Glyoxal (Gly-T)

900 2.30 25(A) 5.09±0.02 0.491 1 19

3000 0.653 55 2.16±0.02 0.36 146

5000 0.392 43 1 .15±0.03 0.205 176

25000 0.0784 35 0.0673±0.0004 0.1 14 258

50000 0.0392 18 0.0427±0.0003 0.0675 324

Pendent-Modified AminopropylPDMS and Glyoxal (Gly-P)

3% 5500 0.258 13 0.241 ±0.004 0.258 160

5% 8000 0.675 58 1 .81 ±0.03 0.349 133

7% 4000 0.946 65 3.23±0.01 0.442 125

10% 2500 1 .35 10(A) 4.45±0.04 0.521 1 16

25% 2000 3.38 32(A) 6.03±0.05 0.702 108

Telechelic-modified aminopropylPDMS and Glutaraldehyde (Glu-T)

900 2.30 74 1 .14±0.02 0.660 135

3000 0.653 54 1 .00±0.04 0.410 155

5000 0.392 47 0.434±0.005 0.341 165

25000 0.0784 33 0.0471 ±0.0003 0.172 220

50000 0.0392 28 0.0298±0.0005 0.121 250

Pendent-modified aminopropylPDMS and Glutaraldehyde (Glu-P)

3% 5500 0.258 25 0.886±0.005 0.181 175

5% 8000 0.675 46 1 .38±0.03 0.277 145

7% 4000 0.946 59 1 .69±0.01 0.364 140

10% 2500 1 .35 71 2.07±0.02 0.592 120

25% 2000 3.38 20(A) 3.29±0.03 0.88 1 15

[0093] To determine the optimal stoichiometry for crosslinking, samples of DMS- A31 (30000 g mol ¹) and DMS-A15 (3000 g mol ¹) were titrated with different amounts of formaldehyde or glyoxal, respectively. The Young’s modulus for these formaldehyde, and glyoxal elastomers were measured to determining the stoichiometry that gives the highest crosslink density (Figure 5 and Figure 7). For formaldehyde it was determined that a 1 : 1 amine to aldehyde ratio gave the largest Young’s modulus, while a 2:1 amine to aldehyde ratio was optimal for glyoxal. Using an amine to aldehyde ratio that is lower than optimal yields softer materials. Adhesion to Different Materials

[0094] The FORM-PDMS elastomers were tested for their adhesive properties by curing aminopropylPDMS using a solution of formaldehyde with a starting [amineo] = [aldehydeo], between two square 1.0 cm² dowels made from a variety of materials (methyl methacrylate, glass, polystyrene, and Teflon). 4% Pendent-aminopropylPDMS was selected to react with formaldehyde in a 1 : 1 amine to aldehyde ratio; the thickness of the elastomer between the surfaces was 10 mm. After being allowed to cure for 30 min, the dowels were pulled apart using an Instron to measure the forces required for elongation at break and to establish if failure was adhesive or cohesive. FORM-PDMS can bind to a variety of surface with no tackiness after full cure. Glass or methyl methacrylate had the strongest adhesion while polystyrene had slightly weaker adhesion, and fluorocarbon materials like Teflon had significantly weaker adhesion (Figure 4). All elastomers experienced adhesive failure, leaving no elastomer adhered to the substrate surface.

Demonstration of the Elastomer as a Sealant

[0095] The adhesive properties of the aldehyde crosslinked silicone elastomers coupled with the ability to cure underwater made them attractive as a hydrophobic sealant that could be applied under water. To demonstrate this five holes 1 cm in diameter were drilled into a 1.5 L polypropylene container (Figure 3A). The container was then filled with 1.25 L of water, which easily flowed through all of the five holes (Figure 3B). To dispense the sealant a 10:1 mixing syringe was used; the larger barrel was loaded with 7 ml_ of DMS-A1 1 (6.55 g, 7.70 mmol) and the smaller barrel was loaded with 0.7 ml_ of formalin solution (0.756 g, 9.32 mmol H2CO). The curing elastomer mixture was extruded from the dual syringe as a white gel into the holes in the container (Figure 3C). The gel quickly solidified into a white elastomer (5s) in the holes preventing any further flow of water from the container (Figure 3D).

[0096] Figure 3: A: Five holes cut into polyethylene container (picture taken from above): B: water leaking from the container. C: Application of sealant derived from DMS- A1 1 and formaldehyde solution, respectively, in a double barrel syringe with mixing tip through the water over about 10 s. D: Non-leaking device 16 s after start of application. E: An overhead view of Figure (A-D), F: The same mixture was used to print elastomeric letters in air; gel time was 12 s. Hydrolytic stability

[0097] Despite the reversibility of imine and aminal bonds in the presence of water, FORM-PDMS have good hydrolytic stability. These materials can be submerged under water (24 h) with very little loss in crosslink density immediately after removing from the water, as determined by Young’s modulus which showed only 3 and 4% decreases for formaldehyde crosslinked materials after drying.

[0098] All publications, patents and patent applications are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety. Where a term in the present application is found to be defined differently in a document incorporated herein by reference, the definition provided herein is to serve as the definition for the term.

REFERENCES

1. Noll, W. J., Chemistry and Technology of Silicones. Academic Press: New York, 1968.

2. Brook, M. A., Silicones. In Silicon in Organic, Organometallic and Polymer Chemistry , Wiley: New York, 2000; pp 256-308.

3. Rambarran, T.; Gonzaga, F.; Brook, M. A., Generic, Metal-Free Cross-Linking and Modification of Silicone Elastomers Using Click Ligation. Macromolecules 2012, 45 (5), 2276-2285.

4. Mansuri, E.; Zepeda-Velazquez, L.; Schmidt, R.; Brook, M. A.; DeWolf, C. E., Surface Behavior of Boronic Acid-Terminated Silicones. Langmuir 2015, 31 (34), 9331- 9339.

5. Zepeda-Velazquez, L.; Macphail, B.; Brook, M. A., Spread and set silicone-boronic acid elastomers. Polym. Chem. 2016, 7 (27), 4458-4466.

6. LaRonde, F. J.; Ragheb, A. M.; Brook, M. A., Controlling silica surfaces using responsive coupling agents. Colloid Polym. Sci. 2003, 281 (5), 391-400.

7. Genest, A.; Binauld, S.; Pouget, E.; Ganachaud, F.; Fleury, E.; Portinha, D., Going beyond the barriers of aza-Michael reactions: controlling the selectivity of acrylates towards primary amino-PDMS. Polym. Chem. 2017, 8 (3), 624-630.

8. Rega, J. Silicone-urethane copolymers. 2010.

9. Bui, R.; Brook, M. A., Dynamic covalent Schiff-base silicone polymers and elastomers. Polymer 2019, 160, 282-290.

10. Hoffman, E. A.; Frey, B. L.; Smith, L. M.; Auble, D. T., Formaldehyde Crosslinking: A Tool for the Study of Chromatin Complexes. J. Biol. Chem. 2015, 290 (44), 26404- 2641 1.

1 1 . Sutherland, B. W.; Toews, J.; Kast, J., Utility of formaldehyde cross-linking and mass spectrometry in the study of protein-protein interactions. Journal of Mass Spectrometry 2008, 43 (6), 699-715.

12. Hopwood, D., Fixatives and fixation: a review. Histochemical Journal 1969, 1 (4).

13. Franzen, A.; Greene, T.; Van Landingham, C.; Gentry, R., Toxicology of octamethylcyclotetrasiloxane (D4). Toxic. Lett. 2017, 279, 2-22.

Claims

CLAIMS:

1. A process for preparing silicone elastomers comprising

(i) combining a compound of Formula (I), (II) or (III):

wherein

R22

I

SL

R^{21 1} ., 0-

2oaryl, ^R" and linear and branched siloxanes, wherein R²¹- R²³ are independently selected from Ci-ioalkyl, C2-ioalkenyl, C2-ioalkynyl, aryl, and linear and branched siloxanes;

n is 0-2000, and when n = 0, m = 2-60, and when n>10, then m = 1 -60% of n, but m must be at least 2;

p is 0-2000;

q = 0-2000, if q = 0, r = r = 2-60, if q>10, then r = 1 -60% of q but r must be at least

2;

with

(ii) a reactive aldehyde in an aqueous solution or dispersion that reacts with the amino group of Y to form a covalent crosslink bond via an imine or aminal linkage.

2. The process of claim 1 , wherein the R¹-R²⁰ are independently or simultaneously selected from Ci-ealkyl, C2-6alkenyl, C2-6alkynyl, C6-ioaryl,

R22

I

Si. έ

R^{21 1} ₂₃0i-

^R and linear and branched siloxanes.

3. The process of claim 2, wherein R¹-R²⁰ are independently or simultaneously selected from Ci salkyl or phenyl.

4. The process of claim 3, wherein , R¹-R²⁰ are Chta.

5. The process of any one of claims 1 to 4, wherein R²³-R²⁵ are independently or simultaneously selected from Ci ealkyl, C2-6alkenyl, C2-6alkynyl and C6-ioaryl.

6. The process of any one of claims 1 o to 5, wherein Y is-R²⁴NH2 or -R²⁴- NHR^a, wherein R^a is Ci ealkyl optionally substituted with amino (NH2).

7. The process of claim 6, wherein R²⁴ is selected from Ci ealkyl, Ci-6alkylene, C2-6alkenyl, C2-6alkenylene, C2-6alkynyl, C2-6alkynylene, C6-ioaryl, or C6-ioarylalkyl.

8. The process of claim 7, wherein Y is

9. The process of any one of claims 1 to 8, wherein the compound of formula (I), (II), or (III) is selected from

10. The process of any one of claims 1 to 9, wherein the reactive aldehyde is formaldehyde.

1 1. The process of any one of claims 1 to 9, wherein the reactive aldehyde is of the formula W-[(C=0)H]b, wherein W is a Ci-i2hydrocarbyl radical and b is an integer 2, 3, 4, 5 or 6.

12. The process of claim 1 1 , wherein the reactive aldehyde is glutaraldehyde or glyoxal.

13. The process of claim 1 , where the siloxane is selected from

where a, b, c and d are integers; c and d 0-1000, if c=0, a+b = 2-60, if c>10, then a+b = 1-60% of c.

14. The process of any one of claims 1 to 13, wherein the reaction between the compound of formula (I), (II) or (III) and the reactive aldehyde is conducted in air or under water.

15. An elastomer comprising:

(i) a compound of Formula (I), (II) or (III):

wherein

R²²

I

Sk S

R^{21 1} "O-f-

n is 0-2000, if n=0, m = 2-60, if n>10, then m = 1-60% of n;

q is 0-2000, if q=0, r = 2-60, if q>10, then r = 1-60% of q;

p is 0-2000;

Y is an amino-modified group, in which the amine is a primary or secondary amine connected to the silicone polymer through a linker R²⁴, wherein the linker R²⁴ is selected from Ci-ioalkyl, Ci-ioalkylene, C2-ioalkenyl, C2-ioalkenylene, C2-ioalkynyl, C2-ioalkynylene, C6-2oaryl, or C6-2oarylalkyl, and wherein the nitrogen atom(s) of the primary or secondary amine is connected to the linker via a sp³ hybridized carbon, and wherein one or more carbons of R²⁴ may be substituted with O, NH, NR or S groups; and

wherein the compound of formula (I), (II), or (III) is crosslinked with a reactive aldehyde.