SU731753A1 - Method of preparing grafted copolymers of (meth) acrylic or allylic monomers or their mixture on solid surfaces - Google Patents

Description

m by irradiating surfaces with ionizing radiation followed by their treatment with the appropriate monomers in the form of a vapor phase or in a mixture of monomer with methyl alcohol C.

In the event that the polymer formed swells well in the reaction medium, the bimolecular chain termination reaction occurs at a high rate, which leads to a relatively low marginal yield of the polymer being poured. In the case of the formation of a polymer that is not soluble in the reaction medium, the radicalizing of the radicals with a high probability occurs, which also leads to a low yield of the graftable polymer. In all the cases discussed above, the graft polymer formation reaction follows the usual laws of radical polymerization, the molecular masses of the grafted polymers are described by the laws of statistics and are difficult to control.

It is known that the use of orthophosphoric acid as a complexing agent in the homopolymerization of methyl methacrylate in an externally homogeneous system leads to an increase in the rate of polymerization and an increase in the molecular weight of the polymer. In this case, a significant amount of long-lived radicals are formed in the system that can grow in the absence of external initiation. living chains and form block copolymers with the introduction of a new monomer, but at the stage of the initiated process the image a significant amount of homopolymer.

The purpose of the invention is to develop a method for producing graft copolymers of acrylic or methacrylic or allyl monomers, or their mixtures on solid organic or inorganic surfaces, having a high degree and speed of grafting, as well as the ability to control the molecular mass characteristics of grafted polymers in the practical absence of homopolymers of grafted monomers.

The goal is achieved by the fact that the method of obtaining graft copolymers of (meth) acrylic or allyl monomers, or their mixtures on solid surfaces, consisting in pre-irradiating the solid surface with a suitable treatment by its corresponding monomers, is carried out in the presence of phosphoric acid at a molar ratio monomers and phosphoric acid 1: 0.3-1: 6, respectively.

Solid surfaces, subject to the exclusion of oxygen, are irradiated with, for example, {j-rays or an electron beam, or x-rays, or UV light, and then brought into contact with a mixture of acrylic or methacrylic or allyl monomers, or mixtures thereof with polar solvents (ketones, esters) and orthophosphoric acid (H „PO /,) with a ratio (monomer + solvent):: () 1: 0.3-1: 6.

Irradiation of solid surfaces can be carried out in a wide range of temperatures, for example, from minus 196 to plus 600 s. Can be used in a wide range of concentrations, for example from 50 to 90%.

The combined use of irradiation of materials, which leads to the formation of radicals fixed on the surface or in the bulk of a solid material, using monomers In the form of their solutions in phosphoric acid provides both practical prevention of bimolecular death of active sites, and prevention of freezing of radicals. Thus, the grafting reaction is initiated by these radicals and the growth response is described by the laws of living chain polymerization. As a result, the number of grafted chains is determined by the number of active sites available to the monomer, the yields and molecular weights of the graft chains are proportional to the contact time of the irradiated materials with the reaction system, and no appreciable amounts of homopolymer of the graftable monomer are observed. At the same time, high graft rates are achieved.

Example 1. 1.0 g of cellulose is irradiated under vacuum at -196 (70 1i rays with a dose of 1, (dose rate 0.5-10 rad / h), then, in the dark, under vacuum conditions, the reaction system is introduced containing 17 , 2 ml of methyl methacrylate and 32.8 ml of 85% orthophosphoric acid (the molar ratio of methyl methacrylate is 1: 3). After the end of the experiment, the product is a homogeneous mass with grafted poly, methyl methacrylate, distributed both on the surface and in volume of cellulose.

The presence of a homopolymer is checked by prolonged extraction of the reaction product with acetone. After the completion of the extraction, the cellulose is dried under vacuum to constant weight and the weight gain is determined. The grafted cellulose is hydrolyzed. And the molecular weight of the graft polymethyl methacrylate chains is determined. The dependence of the weight gain of cellulose and the molecular weight of the grafted polymethyl methacrylate furnaces on the contact time of the irradiated cellulose with the reactive system is shown in Table. one.

Table

The yield of homopolymer was elh2% of the amount of grafted polymethyl methacrylate.

Example 2. 1.040 g of cellulose is irradiated in a medium, argon is focused by NELM with UV lamp light (lamp power 1000 W) for 2 h, then, in the dark, in argon medium a reaction system containing 8.4 ml methyl-CX- is introduced chloroacrylate (MHA), 7,8 t-ll of ethyl acetate (EA) and 33.8 ml of 85% orthophosphoric acid (CMXA + SAJ molar composition system, 1: 3; MHA: EA 1: 1 checked by prolonged extraction of the reaction product with dimethylformamide, then the cellulose was washed with methyl alcohol and dried in a vacuum to constant weight. Contact for 20 min. The weight of grafted cellulose is 1.352 g (30% weight gain). Homopolymer obtained 0.008 g (3% of the amount of grafted polymer), Grafting was carried out on the surface.

Example 3. 0.945 g of cellulose is irradiated under vacuum at -1 ° C-rays with a dose of 1.010 rad (dose rate O, 510 rad / h), then, in the dark, under vacuum conditions the reaction system is injected containing 10 ml of methyl methacrylate, 9 , 5 ml of methyl-Ob-chloroacrylate, 9.2 ml of ethyl acetate and 19.0 ml of 85% orthophosphoric acid (molar system of MMA + + MHA + EA: Na, P04 1: 1; MMA: MHA:: EA 1 : 1: 1). At the end of the experiment, the presence of a homopolymer is checked by long-term extraction of the reaction product with dimethylformamide, then the grafted cellulose is washed with methyl alcohol and dried in vacuum to constant weight. During the 60-minute grafting time, the grafted cellulose weight was 2.032 g (115% gain, mole fraction of PMMA grafted 0.23, mole fraction of PMHA grafted O, 77), Homopolymer gives 0.032 g (-3% of the amount of grafted polymer).

Example 4. 0.938 g of a Teflon film with a thickness of 0.1 mm is irradiated in vacuum at 40 ° C with an electron beam of dose 1, rad (dose rate 0.5–10 rad / min), then at

in the dark, under vacuum conditions, a reaction system is introduced containing 17.2 ml of methyl methacrylate and 32.8 ml of 85% orthophosphoric acid (the molar ratio of methyl methacrylate and acid is 1: 3). The presence of a homopolymer is checked by prolonged extraction of the reaction product with acetone. After the extraction is completed, the film is dried under vacuum to constant weight. During the contact time of 50 min, the weight of the grafted polytetrafluoroethylene is 1.031 g (10% weight gain). Homopolimethyl methacrylate get 0.004 g (4% of the amount of the grafted polymer). Vaccination is carried out on the surface.

5 teflon.

Example 5. 1.0 g of silica gel is irradiated under vacuum at -19b ° C-rays with a dose of 1.0-10 rad (dose rate of 0.510 rad / h), then, in this vacuum, the reaction system containing 1 is introduced 38 ml of methyl methacrylate and 2.62 ml of 85% orthophosphoric acid (the molar ratio of methyl methacrylate and acid is 1: 3). After completing the experience

5, the presence of a homopolymer is checked by prolonged extraction of the reaction product with acetone, then the silica gel is dried under vacuum to constant weight. The grafted silica gel is dissolved in hydrofluoric acid, and the molecular weight of the grafted chains of polymethyl methacrylate is determined.

Dependence of the weight gain of silica gel and the molecular weight of the graft chains

5 of polymethyl methacrylate from the contact time of the irradiated silica gel with the reaction system is shown in Table. 2

table 2

40 45

The yield of homopolymethyl methacrylate is 4% of the amount of polymer grafted.

Claims (4)

Example 6. 0.9 85 g. Silica gel is irradiated in argon medium at 50 ° C with x-rays with a dose of 1.0 x x 10 ° rad (dose rate 6 10 rad / min) and then at 20 ° C in the dark in argon medium the reaction system containing 0.58 ml of butyl acrylate (BA), 0.30 ml of acetone. (A) and 3.12 ml of orthophosphoric acid (system of the molar composition fBA + A: Ho, PO ;, 1: 6, BA: A 1: 1 ). After the grafting is completed, the homopolymer is extracted with acetone, then the grafted silica gel is dried under vacuum to constant weight. During the contact time of 7 minutes, the weight of the grafted silica gel is 1.061 g (weight gain 7.5%), the homopolymer is obtained 0.003 g (based on the amount of the graft polymer). Example 7..1.123 g of silica gel is irradiated under vacuum at -196C if-rays with a dose of 1.010 rad (dose rate OjSlO rad / h), then, in darkness under vacuum conditions, the reaction system containing 3.0 ppm of allylamine and 1, 76 ml of 50% orthophosphoric acid (the molar ratio of allylamine and H PO is 1: 0.3). After the grafting is completed, the homopolymer is washed with water, then the grafted silica gel is dried under vacuum to constant weight. During the contact time of 7 minutes, the weight of the grafted silica gel is 1.180 g (5% weight gain). Homopolymer get 0.003 g (5% of the number of grafted polyallylsmina). Thus, the proposed method allows obtaining graft copolymers of acrylic or methacrylic or allyl monomers or their mixtures on solid organic or inorganic materials at high speeds by varying the molecular weight characteristics. Grafted chains in the practical absence of homopolymers of grafted monomers. DETAILED DESCRIPTION A method for producing graft copolymers (mat) of acrylic or allyl monomers or their mixtures on solid surfaces by pre-irradiating a solid surface with subsequent treatment with its appropriate monomers, characterized in that, in order to increase the degree and speed of grafting, to eliminate the formation of a grafted monomer homopolymer and controlling the molecular weight characteristics of the graftable polymer, the process is carried out in the presence of phosphoric acid at a molar ratio of mono iepoB and phosphoric acid 1: 0.3-1: 6, respectively. Sources of information, spirited in attention during the examination 1. Ceresa R. Block and grafted zopolimer, M., Mir, 1964, p. 26 2. Batter G. Properties of grafted and block copolymers. L., Himi, 1970, p. nineteen. 3. USSR author's certificate according to the application 2443165 / 23-05, cl. C 08 F 255/00, 1977. 4.Bevington I.C. Nature. 178, W 4542, 1956, 1112 (prototype).