Acrylate-methacrylate copolymers

In addition to acting as impact modifiers a number of polymeric additives may be considered as processing aids. These have similar chemical constitutions to the impact modifiers and include ABS, MBS, chlorinated polyethylene, acrylate-methacrylate copolymers and EVA-PVC grafts. Such materials are more compatible with the PVC and are primarily included to ensure more uniform flow and hence improve surface finish. They may also increase gelation rates. In the case of the compatible MBS polymers they have the special function already mentioned of balancing the refractive indices of the continuous and disperse phases of impact-modified compound. 

FIGURE 8.12. SEM images of two inverse opal samples that were fabricated by templating a U V-curable prepolymer to the poly(acrylate methacrylate) copolymer against the opaline lattices of polystyrene beads with different orientations. 

This study illustrates a particular use of FT-Raman spectroscopy (Section 2.4.2) to monitor an emulsion polymerization of an acrylic/methacrylic copolymer. There are four reaction components to an emulsion polymerization water-immiscible monomer, water, initiator, and emulsifier. During the reaction process, the monomers become solubilized by the emulsifier. Polymerization reactions were carried using three monomers BA (butyl acrylate), MMA (methyl methacrylate), and AMA (allyl methacrylate). Figure 7-1 shows the FT-Raman spectra of the pure monomers, with the strong vC=C bands highlighted at 1,650 and 1,630 cm-1. The reaction was made at 74°C. As the polymerization proceeded, the disappearance of the C=C vibration could be followed, as illustrated in Fig. 7-2, which shows a plot of the concentration of the vC=C bonds in the emulsion with reaction time. After two hours of the monomer feed, 5% of the unreacted double bonds remained. As the... 

Jensen JL, Appel LE, Clair JH, Zentner GM. Variables that affect the mechanism of drug release from osmotic pumps coated with acrylate/methacrylate copolymer latexes. / Pharm Sci 1995 84 530-533. 

Gipstein, E., Prime, R. B., and Allen, R., The effect of pressure on the polymerisation cure of acrylate methacrylate copolymers, NATAS, Paper 113 (1991). 

Quartz filter — SPE poly(acrylate-methacrylate) copolymer 95-99%... 

Acrylate-methacrylate copolymers (pure acrylates) are used in particular for house paints and other emulsion paints with high weather resistance and for waterborne industrial paints. 

Chem. Descrip. Acrylic/methacrylic copolymer emulsion CAS 25133-97-5... 

Song, L., W. Hu, H. Zhang, G. Wang, H. Yang and S. Zhu (2010a), In vitro evaluation of chemically cross-linked shape-memory acrylate-methacrylate copolymer networks as ocular implants. Journal of Physical Chemistry B, 114(21) pp. im-im. 

Mehra has used Plextol B-500, an acrylic methacrylate copolymer in dilute solution along with a thickener. He first used hydroxyethyl cellulose to gel the adhesive to keep it at the lamina interface, later he used microspheres to apply the film as a slurry. These lining methods were easily activated in the absence elevated temperatures and only slight pressures. Hacke has used a thickener based on methacryl acid in small concentrations with plextol D360 as another adhesive system for a low pressure activated adhesive [9]. 

In PVC technology certain polymeric additives can be considered as process aids. These polymers have a similar composition to those used as impact modifiers in PVC formulations but are more compatible and so are primarily included to ensure more uniform flow and hence improve surface finish. Such process aids include ABS, chlorinated polyethylene, MBS, EVA-PVC graft polymers and acrylate-methacrylate copolymers. As these are usually found in unplasticised PVC, direct analysis of the product by IR will usually indicate the presence of those that have a distinctive spectmm as no masking by plasticiser will take place. However, even rigid PVC can contain a small amount of phthalate and so it is advisable to carry out a solvent extraction to clean up the matrix first. Where the process aid (e.g., chlorinated polyethylene) has a relatively bland spectmm, a technique such as NMR will be required to both detect and quantify it. NMR will usually be required to quantify the other types as well, unless the spectrum is very distinctive and standards of known composition are available. 

Suspension Polymerization. Suspension polymerisation yields polymer in the form of tiny beads, which ate primarily used as mol ding powders and ion-exchange resins. Most suspension polymers prepared as mol ding powders are poly(methyl methacrylate) copolymers containing up to 20% acrylate for reduced btittieness and improved processibiUty are also common. 

Many synthetic latices exist (7,8) (see Elastomers, synthetic). They contain butadiene and styrene copolymers (elastomeric), styrene—butadiene copolymers (resinous), butadiene and acrylonitrile copolymers, butadiene with styrene and acrylonitrile, chloroprene copolymers, methacrylate and acrylate ester copolymers, vinyl acetate copolymers, vinyl and vinyUdene chloride copolymers, ethylene copolymers, fluorinated copolymers, acrylamide copolymers, styrene—acrolein copolymers, and pyrrole and pyrrole copolymers. Many of these latices also have carboxylated versions. 

Other patents include copolymers of vinyl ketones with acrylates, methacrylates, and styrene (53) an ethylene—carbon monoxide (1—7 wt %) blend... 

One such system involved grafting 70 parts of methyl methacrylate on to 30 parts of an 81-19 2-ethylhexyl acrylate-styrene copolymer. Such a grafted material was claimed to have very good weathering properties as well as exhibiting high optical transmission. 

Radical copolymerization is used in the manufacturing of random copolymers of acrylamide with vinyl monomers. Anionic copolymers are obtained by copolymerization of acrylamide with acrylic, methacrylic, maleic, fu-maric, styrenesulfonic, 2-acrylamide-2-methylpro-panesulfonic acids and its salts, etc., as well as by hydrolysis and sulfomethylation of polyacrylamide Cationic copolymers are obtained by copolymerization of acrylamide with jV-dialkylaminoalkyl acrylates and methacrylates, l,2-dimethyl-5-vinylpyridinum sulfate, etc. or by postreactions of polyacrylamide (the Mannich reaction and Hofmann degradation). Nonionic copolymers are obtained by copolymerization of acrylamide with acrylates, methacrylates, styrene derivatives, acrylonitrile, etc. Copolymerization methods are the same as the polymerization of acrylamide. 

Methyl methacrylate-ethyi acrylate-styrene copolymer >10 9.2 1,7 90 4,400 440 0,020 0,025 ... 

Polymethyl methacrylate (PMMA) octylacrylamide/acrylates/butyl-aminoethyl methacrylate copolymer Plexiglas... 

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. 

Various substituted styrene-alkyl methacrylate block copolymers and all-acrylic block copolymers have been synthesized in a controlled fashion demonstrating predictable molecular weight and narrow molecular weight distributions. Table I depicts various poly (t-butylstyrene)-b-poly(t-butyl methacrylate) (PTBS-PTBMA) and poly(methyl methacrylate)-b-poly(t-butyl methacrylate) (PMMA-PTBMA) samples. In addition, all-acrylic block copolymers based on poly(2-ethylhexyl methacrylate)-b-poly(t-butyl methacrylate) have been recently synthesized and offer many unique possibilities due to the low glass transition temperature of PEHMA. In most cases, a range of 5-25 wt.% of alkyl methacrylate was incorporated into the block copolymer. This composition not only facilitated solubility during subsequent hydrolysis but also limited the maximum level of derived ionic functionality. 

Although the potassium superoxide route can be universally applied to various alkyl methacrylates, it is experimentally more difficult than simple acid hydrolysis. In addition, limited yields do not permit well-defined hydrophobic-hydrophilic blocks. On the other hand, acid catalyzed hydrolysis is limited to only a few esters such as TBMA, but yields of carboxylate are quantitative. Hydrolysis attempts of poly(methyl methacrylate) (PMMA) and poly(isopropyl methacrylate) (PIPMA) do not yield an observable amount of conversion to the carboxylic acid under the established conditions for poly(t-butyl methacrylate) (PTBMA). This allows for selective hydrolysis of all-acrylic block copolymers. 

Figure 3. Time dependence of the fraction R of unreacted aminostyrene residues during acetylation by 0.14 M acetic anhydride at 30°C. Methyl methacrylate copolymer in acetonitrile solution (0) linear poly-(methyl methacrylate-co-butyl methacrylate) swollen with acetonitrile Cd) methyl methacrylate copolymer crosslinked with 1 mole% ( ) and with 15 mole% ( ) ethylene dimethacrylate poly(methacrylate crosslinked with 3 mole% ethylene dimethacrylate containing entrapped poly(methyl acrylate-co-aminostyrene) ( ).

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