CS238772B1 - Process for grafting polymers or copolymers - Google Patents

Abstract

The invention relates to the grafting of polymers or copolymers containing ester groups in the side chains with macroanions in an environment in which the anions are deactivated only by reactions with ester groups. The grafting macroanions are prepared by transforming the macrocations by the effect of a twofold molar excess of dianions. The invention allows the properties of the copolymers to be varied within wide limits.

Description

The invention relates to the production of graft polymers and copolymers.

The graft copolymers have an irreplaceable role in the plastics field. Their importance is increasing, especially for their compatibilizing effects, allowing the preparation of mixtures of materials incompatible with each other. E.g. blends of two Si more rewarding polymers, blends of polymers with fillers, stabilizers, colorants, plasticizers, etc.

The grafting of polymers with ester groups in the branch chains by conventional methods - for example by re-esterification, mechanically Si by irradiation of the polymer blends with high energy beams - is difficult. Usually it has low efficiency and poorly defined products are produced.

In 1962, however, Micengendler and Andrejev and coworkers (Vysokomol. Soedin £, 1 367 (1962), 8, 2 129 (1966) and later also Rempp (Pure Appl. Chem. £ 6, 403 (1968)) described relatively simple and elegant macroanion grafting:

(in equation (1), z denotes a polymer chain, β denotes a polymeric carbanion either free or coupled to a paired-ion pair, usually an alkali metal cation). The reaction proceeds with high efficiency. According to MS. No. 233,679, reaction (1) can be used to graft branched ester groups in polymers with polymeric silanolate ions. An analogous grafting with alcoholate ions is known, for example, from GB 1439069.

We have now found a significant enrichment in the selection of grafting macroanions and thus the penetrating extension of possible interventions into the structure of the resulting graft copolymer.

So also its physical and chemical properties. Accordingly, the present invention provides a process for grafting polymers or copolymers containing ester groups in the side chains by reaction with macroanions in an environment in which anions are deactivated virtually only by reactions with ester groups in which the macanions are formed by transforming the macanions by a double molar excess of dianions. The synthesis of the graft copolymers of the present invention consists of two steps: In the first one, a macroanion is prepared by ionic polymerization, optionally by copolymerization of a cationic polymerizing moriomer or cationic copolymerizing monomers. This polymerization is initiated by mono-functional cationic oligonators with a stable ions, for example CH CHC CC S CCb ^ (CH ^).

CgHjCO ASPG, CP ₃ C0PP _g j CO-C1O CH _4, etc.

Suitable monomers are, for example, tetrahydrofuran, dioxolane, oxepane, alkyl vinyl ethers, etc., and mixtures thereof, or their sequential delivery to growth centers, so that the macrocation formed has the character of a homopolymer or a random or block copolymer, respectively. This macrocation is then transformed with exactly the same molar amount of dianion, either oligomeric - such as the alkali metal salt of tetramer <methyl styrene dianions - or polymeric, for example, polystyrene or polydimethylsiloxane dianions of suitable molecular weight (from 400 to 100,000 ). When polymeric dianion is used for the transformation, the resulting graft macroanion always has the character of block copolymers, at least diblocks. The transformation is carried out according to AO 236 330 in an environment not chemically reactive with ions.

In a second step, the solution of the above-prepared macroanions is mixed with a solution of a suitable polymer containing ester groups in the side chains, for example with solutions of polymers (copolymers) of esters of acrylic, methacrylic, fumaric, maleic, angelic, etc. Again, the ester groups must not deactivate the anions other than by reacting them with the ester groups. This includes physical conditions, such as temperature.

The process for preparing the graft copolymers of the present invention is further illustrated by several specific examples:

He did

1.5 g of 100,000 molecular weight polymethyl methacrylate was dissolved in 50 cm @ 3 of tetrahydrofuran; solution A was formed in another reactor. 0.18 mmol of CH COCO ^B1ClC was added to 20 cnP of tetrahydrofuran and stored at 263 K. After three days (during which 17,000 molecular weight polytetramethylene oxide macrocations formed) 0 was added to the macrocation solution 0. 18 millimoles of tetramer-.alpha.-methyl styrene dianion sodium, also at 263 K. This transformed the polymer cations into macroanions to form solution B;

Thereafter, solutions A and B were mixed, again at 263 K. All the operations described above were carried out on a high vacuum line to prevent inactivating ions from contaminating any of the solutions. Three hours after mixing of solutions A and B, the mixing reactor was cut, the product precipitated with methanol, washed several times with methanol and dried to constant weight.

The possibly present polytetramethylene oxide copolymer can be removed from the graft copolymers by extraction with hot isopropanol.

The copolymer thus prepared is a polymethyl methacrylate internally softened polytetramethylene oxide graft. It blends very well with the polymethyl methacrylate copolymer and added to it, softens it as well.

Example 2

As in Example 1, but instead of the tetramer sodium salt of C-methyl styrene, 20,000 dianion polystyrene was used in the preparation of solution B. The grafts in the product formed diblocks of CH 2 -CH 2 Ph 2. The softening effect of the copolymers was less than in Example 1, but its surfactant effects were highlighted, for example, in tetrahydrofuran and toluene solutions, in which heterogeneous emulsion-like systems were formed in the presence of poly (methyl methacrylate) and polystyrene homopolymers.

Example 3

The procedure was as in Example 1, but instead of the sodium salt of tetramer O-methyl styrene, a silanolate dianion of molecular weight 75,000 was used in the preparation of solution B.

The bolts in the product formed diblocks -. The softening effect of the copolymer over the copolymers of Example 1 was significantly greater.

Example 4

The procedure was as in Example 1, but instead of tetrahydrofuran, a mixture of 75% tetrahydrofuran and 25% oxetane (molar) was used in the preparation of solution B. The graft copolymers had the character of a random copolymer of the two monomers, and the copolymer had the advantageous characteristics of a synthetic leather finish.

Example 5

The procedure was as in Example 3, but methyl acrylate was used instead of polymethyl methacrylate in the preparation of solution A. The copolymer obtained was used to treat mineral fillers, for example calcium carbonate, before mixing them with polymers, especially polyacrylates.

Příkjad 6

Proceeding as in Example 3, but instead of polymethyl methacrylate in the preparation of solution A, a copolymer of styrene with methyl maleic ester was used. The resulting graft copolymer reduced the brittleness of polystyrene and increased the compatibility of polystyrene with mineral fillers and organic stabilizers.

The graft copolymers prepared according to the present invention can be synthesized so that their structure maximally meets the intended use and desired properties. Copolymers of the structure as allowed by the application of the present invention are not yet available in other ways. Such copolymers have compatibilizers. effects on polymer blends, as polymers internally softening, affect the distribution and application of Van der Waals forces at the interface phase (interfacial activity).

Claims (1)

SUBJECT OF THE INVENTION Process for grafting polymers or copolymers containing ester groups in side chains by reaction with macroanions in an environment in which the anions are deactivated practically only by reaction with ester groups, characterized in that the macanions used are macrocations prepared by the transformation of macrocations by double molar excess of dianions.