Copolymers, block methacrylate containing

By employing anionic techniques, alkyl methacrylate containing block copolymer systems have been synthesized with controlled compositions, predictable molecular weights and narrow molecular weight distributions. Subsequent hydrolysis of the ester functionality to the metal carboxylate or carboxylic acid can be achieved either by potassium superoxide or the acid catalyzed hydrolysis of t-butyl methacrylate blocks. The presence of acid and ion groups has a profound effect on the solution and bulk mechanical behavior of the derived systems. The synthesis and characterization of various substituted styrene and all-acrylic block copolymer precursors with alkyl methacrylates will be discussed. 

Table 5. Summary of methacrylate containing block copolymers prepared using ATRP methods ...

Block copolymers of the ABA type made from hydrocarbon monomers by anionic polymerization have been extensively investigated (1, 2). Much less has been done with nonhydrocarbon block pol3niiers. Such systems as have been repotted show even broader temperature ranges of technical utility than the more familiar styrene/diene/styrene systems (3, 4, 5). It is the purpose of this paper to describe a process for preparing polymethyl methacrylate containing triblock copolymers. The physical property balances that can be gotten and the photooxidative degradation processes that occur will also be covered. 

Breiner et al. (36) studied the so-called knitting pattern found for the triblock copolymer polystyrene-h/ock-poly(ethylene-5 tot-butylene)-h/c c -poly(methyl methacrylate) see Figure 13.17. [The poly(ethylene-5 tflt-buty-lene)-component was formed by hydrogenating the original polybutadiene block, which contained some 1,2-placements as well as the more usual 1,4-placements.] In this morphology, poly(methyl methacrylate) forms peristaltic lamellae in which opposite maxima and minima are spanned by ellipsoidalshaped cylindrical poly(ethylene-co-butylene). Of course, such complexity arises from the combined need of the chains to be able to wander from domain... 

The method lends itself to a demonstration of the fact that certain poly(methyl methacrylate) polymers are block copolymers of isotactic and syndiotactic conformation, not to mention that conventional, i,e., free-radically polymerized, poly(methyl methacrylate) contains a substantial fraction of the isotactic polymer. 

Akutin and co-workers [159] made block and graft copolymer of fluorine-containing polymers or polysiloxanes as one component and poly(methyl methacrylate), poly(vinyl chloride), and ethylcellulose as the second. During the irradiation, samples were withdrawn at regular intervals in order to determine the extent of reaction by the decrease in solution viscosity, rj. In other cases, a recombination of macroradicals into new polymeric species caused an increase in the viscosity. The sign and rate of change of rj was thus different for different systems. 

A number of papers have discussed the polymerisation of silicon-containing 4-membered ring monomers, DASCB [29-33]. Typical polymerisation conditions are /THF, nHx/nBuLi/ 48 C/ZCHsOH/. Block copolymers of methacrylates and S, HEMA, MMA, and tBMA were prepared with alkyl = Bu (Mn/(kg/mol) < 17 1.13 < Mw/Mn < 1.25 for HEMA block... 

Copolymers containing carbonyl groups in the main chain have been used in early works as photoinitiators. These copolymers undergo main chain scission upon irradiation. In the presence of the vinyl monomer, the terminal radicals react with the monomer, initiating its polymerization. Following this method, various block copolymers (second comonomer in the block copolymer methyl methacrylate) have been obtained. See Table 18. 

Block copolymers of vinyl acetate with methyl methacrylate, acryflc acid, acrylonitrile, and vinyl pyrrohdinone have been prepared by copolymeriza tion in viscous conditions, with solvents that are poor solvents for the vinyl acetate macroradical (123). Similarly, the copolymeriza tion of vinyl acetate with methyl methacrylate is enhanced by the solvents acetonitrile and acetone and is decreased by propanol (124). Copolymers of vinyl acetate containing cycHc functional groups in the polymer chain have been prepared by copolymeriza tion of vinyl acetate with A/,A/-diaIlylcyanamide and W,W-diaIl5lamine (125,126). 

Isocyanates can be added to solvent-borne CR adhesive solutions as a two-part adhesive system. This two-part adhesive system is less effective with rubber substrates containing high styrene resin and for butadiene-styrene block (thermoplastic rubber) copolymers. To improve the specific adhesion to those materials, addition of a poly-alpha-methylstyrene resin to solvent-borne CR adhesives is quite effective [76]. An alternative technique is to graft a methacrylate monomer into the polychloroprene [2]. 

Seymour and coworkers (27,28,29,30) actually used these composition gradients to prepare block copolymers by swelling particles containing occluded (i.e., living) macroradicals with a second monomer. Such block copolymers were prepared from occluded vinylacetate, methyl methacrylate, and acrylonitrile macroradicals, and the yield of block copolymers was studied as a function of the solubility and rate of diffusion of the swelling monomer in the particles. 

AB Block Copolymers Containing Methacrylic Acid and/or Metal Methacrylate Blocks... 

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