Methyl methacrylate polymer with

Methyl Methacrylate Polymers with Enhanced Impact Resistance 413... 

METHYL METHACRYLATE POLYMERS WITH ENHANCED IMPACT RESISTANCE AND SOFTENING POINT... 

Materials. The dispersed phase of the dispersions contained, by weight 98.07% acrylic polymer beads, 0.8% benzoyl peroxide (98% active), 1% red acetate fibers, 0.03% red pigments, and 0.1% Ti02 pigment. The acrylic polymer beads were a 50/50 wt/wt blend of two suspension polymerized poly (methyl methacrylate) polymers with solution molecular weights of 160,000 and 950,000. Additives to the dispersed phase were those described above. The polymers were each reduced 1 vol % on the total dispersion volume to compensate for the additives. 

Although original water samples can apply for some techniques, the isolation procedure is essential for better HS characterization with most analytical techniques. The traditional HS isolation method probably is XAD adsorption, which has been widely used for decades in the HS isolation from waters, soils, and organisms. This method can not only isolate HS, but also further separate HS into two fractions (humic acid and fulvic acid). Detailed isolation procedures have been reviewed in previous articles.XAD resins are styrene-divinylbenzene or methyl methacrylate polymer with various hydrophobicities and cross linkages. The resins adsorb dissolved organic matter mainly by hydrophobic binding or weak interactions such as Van Der Waals force, but the exact mechanism of adsorption is still unknown. 

Laine, O., Trimpin, S., Raeder, H.J., and Muellen, K. (2003) Changes in post-source decay fragmentation behavior of poly(methyl methacrylate) polymers with increasing molecular weight studied by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Eur. J. Mass Spectrom., 9, 195-201. 

Place 25 g. of methyl methacrylate polymer (G.B. Diakon (powder). Perspex (sheet) U.S.A. Lucite, Plexiglass) in a 100 ml. Claisen flask, attach an efficient condenser e.g., of the double smface type) and distil with a small luminous flame move the flame to and fro around the sides of the flask. At about 300° the polymer softens and undergoes rapid depolymerisation to the monomer, methyl methacrylate, which distils over into the receiver. Continue the distillation until only a small black residue (3-4 g.) remains. Redistil the hquid it passes over at 100-110°, mainly at 100-102°. The yield of methyl methacrylate (monomer) is 20 g. If the monomer is to be kept for any period, add 0 -1 g. of hydro quinone to act as a stabiUser or inhibitor of polymerisation. 

Figure 7.10 shows the 60-MHz spectra of poly (methyl methacrylate) prepared with different catalysts so that predominately isotactic, syndiotactic, and atactic products are formed. The three spectra in Fig. 7.10 are identified in terms of this predominant character. It is apparent that the spectra are quite different, especially in the range of 5 values between about 1 and 2 ppm. Since the atactic polymer has the least regular structure, we concentrate on the other two to make the assignment of the spectral features to the various protons. 

AH-acryHc (100%) latex emulsions are commonly recognized as the most durable paints for exterior use. Exterior grades are usuaHy copolymers of methyl methacrylate with butyl acrylate or 2-ethyIhexyl acrylate (see Acrylic ester polymers). Interior grades are based on methyl methacrylate copolymerized with butyl acrylate or ethyl acrylate. AcryHc latex emulsions are not commonly used in interior flat paints because these paints typicaHy do not require the kind of performance characteristics that acryHcs offer. However, for interior semigloss or gloss paints, aH-acryHc polymers and acryHc copolymers are used almost exclusively due to their exceUent gloss potential, adhesion characteristics, as weU as block and print resistance. 

Various methacrylate esters have been disclosed as modifiers of DADC. Thus methyl methacrylate polymer may be dissolved in DADC and the sheets cast (22). When DADC is copolymerized with methyl methacrylate, a silane derivative may be added to control the release from the mold (23). 

There are some indications that the situation described above has been realized, at least partially, in the system styrene-methyl methacrylate polymerized by metallic lithium.29 29b It is known51 that in a 50-50 mixture of styrene and methyl methacrylate radical polymerization yields a product of approximately the same composition as the feed. On the other hand, a product containing only a few per cent of styrene is formed in a polymerization proceeding by an anionic mechanism. Since the polymer obtained in the 50-50 mixture of styrene and methyl methacrylate polymerized with metallic lithium had apparently an intermediate composition, it has been suggested that this is a block polymer obtained in a reaction discussed above. Further evidence favoring this mechanism is provided by the fact that under identical conditions only pure poly-methyl methacrylate is formed if the polymerization is initiated by butyl lithium and not by lithium dispersion. This proves that incorporation of styrene is due to a different initiation and not propagation. 

Figure 8. Computed drift curves for instantaneous and cumulative CCs of styrene-methyl methacrylate polymers initiated with AIBN...

We have recently initiated our investigation of blends by examining the compatibility between our modified polymer sample 4 and poly(methyl methacrylate). Mixtures with a composition of between 10% and 30% of sample 4 yield compatible blends which are transparent under a polarized light microscope, and are characterized by a single Tg. Mixtures richer than 60% of 4 undergo complete phase separation. 

Figure 1 shows the exposure characteristics of atactic and isotactic poly(a,a-dimethylbenzyl methacrylate) resists with CH3ONa development together with those of the poly (methyl methacrylate) resist with MIBK/IPA development. Poly(a,a-dimethylbenzyl methacrylate) s showed high sensitivity and very good contrast between exposed and unexposed areas. The atactic polymer with alkaline development was improved in the sensitivity and 7-value by a factor of more than three over poly(methyl methacrylate) with MIBK/IPA development. 

M. Fowler, J. Barlow, and D. Paul, Effect of copolymer composition on the miscibility of blends of styrene-acrylonitrile copolymers with poly (methyl methacrylate), Polymer, 28(7) 1177-1184, June 1987. 

One of the first detailed studies on these systems was that of Beaman (26), who showed that methacrylonitrile polymerizes by an anionic chain mechanism when treated with various bases, including Na in liquid ammonia at —75° C. He noted also that low molecular weight polymers are obtained from reaction of acrylonitrile with butylmagnesium bromide. Foster (56) extended the liquid ammonia method to copolymerization studies in which acrylonitrile was combined with styrene, with methyl methacrylate and with vinyl butyl sulfone. Satisfactory data were obtained only with the sulfone, in which case there was some tendency for alternation. 

Mixtures of poly(vinylidene fluoride) with poly (methyl methacrylate) and with poly (ethyl methacrylate) form compatible blends. As evidence of compatibility, single glass transition temperatures are observed for the mixtures, and transparency is observed over a broad range of composition. These criteria, in combination, are acceptable evidence for true molecular intermixing (1, 19). These systems are particularly interesting in view of Bohns (1) review, in which he concludes that a compatible mixture of one crystalline polymer with any other polymer is unlikely except in the remotely possible case of mixed crystal formation. In the present case, the crystalline PVdF is effectively dissolved into the amorphous methacrylate polymer melt, and the dissolved, now amorphous, PVdF behaves as a plasticizer for the glassy methacrylate polymers. 

The effect of non-uniform polymer composition is shown in Figure 11 for the case of a 50/50-methyl methacrylate/ethyl acrylate copolymer made by a linear power feed process in which the near tank initially contained only ethyl acrylate and the far tank only methyl methacrylate. Compared with its uniform counterpart, the non-uniform polymer had a T D approximately 25° lower and a respectable... 

J.R. Ebdon, D. Price, B.J. Hunt, P. Joseph, F. Gao, G.J. Milnes, and K.L. Cunhffe, Flame retardance in some polystyrenes and poly(methyl methacrylate)s with covalently bound phosphorus-containing groups Initial screening experiments and some laser pyrolysis mechanistic studies. Polym. Degrad. Stab., 69, 267-277 (2000). 

Price, D., Pyrah, K., Hull, T. R., Milnes, G. J., Ebdon, J. R., Hunt, B. J., and Joseph. P., Flame retardance of poly(methyl methacrylate) modified with phosphorus-containing compounds, Polym. Degrad. Stab., 2002, 77, 227-233. 

In Fig. 13 are shown typical spectra for 15% solutions of two methyl methacrylate polymers in chloroform. The polymers were prepared with (a) benzoyl peroxide in toluene at 100° and (b) n-butyllithium at — 62°. The large peak at the left is that of the chloroform solvent. The ester methyl group appears at 6.40r in both spectra, and is not affected by the chain conformation. There are three cc-methyl peaks, at 8.78t, 8.95 t, and 9.09r, whose relative heights vary greatly with the method of polymer preparation. Polymers prepared with n-butyllithium show a very prominent peak at 8.78r, the others being much smaller. Polymers prepared with benzoyl peroxide initiator show the same three peaks, but now the peak at 9.09r is the most prominent. 

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