CS267639B1 - Method of alkenes' copolymers with siloxanes production - Google Patents

Abstract

Grafted and block copolymers of alkenes with siloxanes are obtained by polysiloxane reaction with polyalkeny, on whose chains were generated by low molecular weight dications or Lewis acids cation centers. It is preferred to perform to react in the presence of 20 to 70% of Raol water, based on the initiator used, Polysiloxanes may have methyl, vinylovc, phenylene and tri-chloropropyl or cyanopropyl substituents a copolymers are useful for manufacturing Composites.

Description

The present invention relates to a process for modifying polyalkenes with polysiloxanes using macroion reactions. Industrially produced polyalkenes (polypropylene, polyethylene and copolymers of propene or ethylene with higher 1-alkenes) are filled with mineral fillers for various reasons. The technical problem is to ensure the compatibility of the hydrocarbon polymer and the filler, which is usually more or less polar in nature. Polyalkenes are not compatible with fillers. The problem is usually solved by modifying the filler, which essentially consists in forming a layer on the surface of its particles that has a greater affinity for the polymer than the filler itself and which could eventually amortize the negative forces and stresses caused by various factors at the interface polymer-filler phase,

- Another way to improve the compatibility of polymer-filler mixtures is to modify the polymer itself. If we can incorporate blocks or grafts of polymers having an affinity of 1 «into the matrix polymer chains. If the blocks or grafts are covalently bonded to the polyalkenes, disparate materials cannot be separated and the composites are in a wide range of fillers. temperature range and intensity of applied forces constant. In addition, if the blocks or screws have an elastic character, they can effectively dampen the interphase stresses. The result is better mechanical properties of composites. Blocks and grafts that melt at a lower temperature than crystalline polyalkene or have an elastomeric character can effectively reduce melt viscosity when processing a composite. This greatly simplifies processing. The potential energy savings in the processing of well-flowing mixtures are not negligible either. It can be expected that a relatively small proportion of modified polyalkenes relative to the polymeric filler matrix will be sufficient to ensure compatibility.

It is known that cationic active centers can be generated on polyalkene chains on which they can polymerize suitable monomers (including cyclic siloxanes - AO 240 627) or which react directly with heteroatoins of polymer chains to form block and / or graft copolymers (AO 238 240, AO 248 854), Applying these findings, it was possible to develop a process for the synthesis of a copolymer of polyalkenes with polysiloxanes by cationic bonding of chains of two homopolymers.

The present invention relates to a process for the preparation of copolymers of polyalkenes with siloxanes by modifying polyalkenes with polysiloxanes, in which cationic centers are generated on polyalkene chains by means of low molecular weight dications or Lewis acids.

The invention furthermore relates to a process for the preparation of copolymers of alkenes with siloxanes, in which the reaction of polysiloxanes takes place in the presence of 20 to 70% of molar water, based on the concentration of initiator.

Extremely low glass transition temperature, good UV and oxidation resistance, high thermal stability and low surface energy predetermine polysiloxanes for use in surface modifications of polymers. Polysiloxane chains anchored to a thermoplastic matrix can improve the sliding properties of machine materials. Therefore, the use of copolymers with siloxanes for the production of mechanical transmissions from plastics seems to be very promising.

Modification of polyalkenes is generally difficult. Hydrocarbon chains are very unstable to the effects of common chemical agents. Only under extreme conditions do these agents attack them. Usually, however, this leads to the irreversible destruction of macromolecules with all the adverse consequences.

Particularly suitable for the formation of cationic active centers are polyalkenes containing acidic hydrogen on a tertiary carbon atom (eg polypropene, poly (1-butene), poly (1-hexene)) and all copolymers having propene, 1-butone molecules incorporated in their chains. 1-hexone or other 1-alkenes. The formation of carbocations on these polyalkenes and the subsequent reaction with polysiloxanes produces graft copolymers. Graft

CS 267 639 B1 linear polyethylene is more difficult in this respect.

Another site on polyalkene chains suitable for dication attack is the polar C-metal bond from the Ziogler-Natt center of coordination polymerization of alkenes. By reaction with the modifying component, block copolymers are then formed. Also, cleavage of the C-C bond in the backbone of the polyalkenes with Lewis acids can give rise to cationic active centers which react with the heteroatoms of the siloxane chain to form block copolymers.

Siloxonium dication can be used as oligomeric dications

Ο1 _{Ο /} Θ dication bis (perchlorate) - 2,2 '- octamethylene - bis (1,3 - dioxolenylia)

C10 ₄ ©

(CH 2) 8

cio ₄ ® dications of the tetrahydrofuran type, e.g.

cf ₃ so ₃ ®

(ch ₂ ) ² 4

O (CH) ² 4u

cf ₃ so ₃ ® or reaction products of aromatic and aliphatic dihalides with AgClO 2

CIO4

Θ C10 ₄

Θ ©,, C10 ₄ CH ₂ - (CH ₂ ) 6

Θ Θ

CH ₂ C10 ₄

From Lewis acids it is possible to use eg PF $,

_{SbF 5} , AsF ₅ , SbCl ₅ , FSO ₃ H and CF 3 OHH.

The generation of cationic active centers on polypropylene chains proceeds according to the following scheme:

C-C and so on:

© | I ©

Si u Si ^ .CH ₂ ch ₃

CH

CH.

ch ₃

© I Si

Yes

Yes

CH_

I ->

u Si —CH- - CH I Λ ch ₃ '2 --- ^CH ·

CH ^CH 2 ch ₃

CH,

CS 267 639 B1

C-H and talc:

^ 3

CH CH.CH.

I 3 i 31 3

CH ₂ - CH r.CH ₂ - C - CH _O - CH nz +

I © I © | ©

In Si HSi in Si

I Il

CH. CH.CH.

3 I 3f 3

CH- - CH ^ a ^ cn - C - CH ₀ —CH rv + H. fc * 4A ©

Polysiloxanes with methyl, phenyl, vinyl, trifluoropropyl and cyanopropyl substituents are used as modifying components.

The copolymers are prepared in 2 stages in a high-vacuum apparatus, which minimizes the possibility of contamination of the ion centers. First, the initiator interacts with the dried polyalkene, forming cationic active centers on the surface of the polymer matrix. The interaction takes place at temperatures of 253-295 K for 1 day. In the second stage, the polyalkenes themselves are modified with polysiloxanes by adding a modifying component and a coinitiator (benzene saturated with water). The modification can be performed at room temperature for 7 days. The synthesis is advantageous for increasing the efficiency of water initiation (molar ratio of initiator: HgO = 1: 0.2 to 0.7, yields of copolymers are lower in the absence of coinitiator. After isolation in methanol and drying of the sample, siloxane homopolymers are extracted (benzene) The separation of homopolymers is not necessary in some cases for the preparation of composites.

The following examples illustrate the invention. % in the examples are by weight.

Example 1 To 1.5 S of isotactic polypropylene (PP) Mosten, dried under a vacuum of 10 ^-2 - 10 ^- Pa Pa and suspended in 20 cm ^{3 of} benzene, 0.1 mol of the siloxonium dication ClO 2 (CH) was added at room temperature. ₃ ) ₂ £ 0 - Si _ ₀ _ Si (CH ₃ ) ₂ C10 ₄ ). After distilling off the benzene to disperse the initiator and the dication interact with the PP for 1-3 days at room temperature, 1 g of poly (dimethylsiloxane) (Mn = 400,000) dissolved in 20 cm 3 of benzene and 0.05 mmol of co-initiating amount were added to the reactor. water in benzene. After 7 days of modification at room temperature, the product was precipitated in methanol and extracted with n - heptane (dissolves unanchored polydimethylsiloxane).

We obtained 2.2 g of copolymers, i.e. that we attached 70 ‘S siloxane chains from the polydimethylsiloxane charge to the isotactic polypropylene matrix.

Example 2

The procedure is as in Example 1, but instead of polydimethylsiloxane, poly (diphenylsiloxane) is used and the molar ratio of initiator with one-time co-initiating water is OK: II _n 0 = 1: 0.3. 2.2 g of copolymers with interfacial activity are obtained.

Example 3

The procedure is as in Example 1, but the modifying component is 1 g of polysiloxane with methyl and trifluoropropyl substances. Cleavage of siloxane chains is accompanied by reactions of h CS 267 639 B1 cations with trifluoropropyl groups. Amount of modifying component in the copolymer = 62 γ, calculated on the starting 1 g of polysiloxane.

Example '1

Following the procedure described in Example 1, a polysiloxane containing cyanopropyl groups was used instead of polydimothylsiloxane. The amount of bound polysiloxane from a 1 g batch is 58 Jo.

Example 5

The procedure was the same as in Example 1, but the modifying component was a polysiloxane with vinyl substituents. Modifications are accompanied by the formation of a certain proportion insoluble in the extracting agent. This crosslinked portion must be removed before verifying the compatibilization efficiency of the copolymer. Content of bound polysiloxane in the unreinforced product = 41 l (based on the starting amount of modifying polymer).

Example 6

The procedure of Examples 1-6, however, modifies the ethylene-propylene copolymer. Yields of 1.8-2.3 S again have strong interfacial active effects.

Example 7

The procedure is as in Examples 1-6, but we modify the matrix of the copolymer of ethylene with 1-butener. Mass of insolubles = 1.9-2.1 g.

Example 8

The procedure is as in Examples 1-6, instead of polypropylene, polyethylene Liten is modified. 1.7-1.8 g of copolymer are obtained (polyethylene is less reactive than polypropylene).

Example 9

Following the procedure of Examples 1-7, but using SbF 8 for the generation of cationic active centers, copolymers of polysiloxanes with polyalkenes containing 51-78% (based on feed) of the siloxane component can be prepared. The interaction time can be reduced to 1 h.

Example 10

The procedure was as in Examples 1-11, but a dication of the p-xylene-diylia dichlorate type was used instead of the siloxonium dication to form cationic active centers (see Chem. Av. 33/58, 532 1983). The amount of bound siloxane chains will no longer increase significantly.

Claims (2)

A process for the preparation of copolymers of alkenes with siloxanes by modifying polyalkenes with polysiloxanes, characterized in that cationic centers are generated on the polyalkene chains by means of low molecular weight dications or Ccis acids, with which polysiloxanes containing methyl, vinyl, phenyl, triufloropropyl cyanide are reacted. 2. A process for the preparation of copolymers of alkenes with siloxanes according to claim 1, characterized in that the reaction of polyalkenes with polysiloxanes takes place in the presence of 20-7 ° molar water, based on the initiator used.