Methyl methacrylate, MMA

The dynamic mechanical properties of VDC—VC copolymers have been studied in detail. The incorporation of VC units in the polymer results in a drop in dynamic modulus because of the reduction in crystallinity. However, the glass-transition temperature is raised therefore, the softening effect observed at room temperature is accompanied by increased brittleness at lower temperatures. These copolymers are normally plasticized in order to avoid this. Small amounts of plasticizer (2—10 wt %) depress T significantly without loss of strength at room temperature. At higher levels of VC, the T of the copolymer is above room temperature and the modulus rises again. A minimum in modulus or maximum in softness is usually observed in copolymers in which T is above room temperature. A thermomechanical analysis of VDC—AN (acrylonitrile) and VDC—MMA (methyl methacrylate) copolymer systems shows a minimum in softening point at 79.4 and 68.1 mol % VDC, respectively (86). 

ACPA azobis(4-cyanopentanoic acid) AIBN azobis isobutyronitrile) BPO benzoyl peroxide DVB divinyl benzene, EGA 2-ethylcyano-acrylate HPC hydroxypropyl cellulose MMA methyl methacrylate PAAc polyacrylic acid PEI polyethyleneimine, PEO/PPO polyethylene oxide/polypyropylene oxide copolymer PVME polyvinylmethylether PVP polyvinylpyrrolidone K-30 DMSO dimethylsulfoxide PGA polyglutaraldehyde CMS chloromethylstyrene PMMA-g-OSA polymethylmethacrylate grafted oligostearic acid. 

MMA methyl methacrylate PMMA poly(methyl methacrylate)... 

It is known that the polymerization of MMA. .. SnCl4 and (MMA)2. .. SnCl complexes (MMA = methyl methacrylate) yields a polymer which predominantly exhibits an isotactic structure90). From the analogy between these complexes and those discovered by the author of this article (MA. .. SnR3), it can be suggested that free-radical copolymerization of MA with trialkylstannyl methacrylates yields copolymers mainly exhibiting configuration19). 

St styrene, MMA methyl methacrylate, IB isobutene, VAc vinyl acetate, VC1 vinyl chloride, DiPF diisopropyl fumarate, AA acrylic acid, MAn maleic anhydride, IBVE isobutyl vinyl ether. 

Figure 5. Amount of absorbed fibrinogen on copolymer surface including hydrophilic domain at 37 C. GEMA glucosyloxyethyl methacrylate, HEMA 2-hydroxyethyl methacrylate, MMA methyl methacrylate, GEMA-MMA poly(GEMA-co-MMA), and HEMA-MMA poly(HEMA-co-MMA).

Abbreviations coiX-V] = copolymers of X and Y colX-b-Yl = block copolymers of poly X and poly Y ST = styrene MA = methyl acrylate MMA = methyl methacrylate AN = acrylonitrile BD = butadiene LR (liquid rubbers) = a, cj-polybutadiene-diols and -dicarboxylic acids Cell-Ac = cellulose acetate Cell-N02 = cellulose nitrate. 

IPNs are also attractive for development of materials with enhanced mechanical properties. As PDMS acts as an elastomer, it is of interest to have a thermoplastic second network such as PMMA or polystyrene. Crosslinked PDMS have poor mechanical properties and need to be reinforced with silica. In the IPNs field, they can advantageously be replaced by a second thermoplastic network. On the other hand, if the thermoplastic network is the major component, the PDMS network can confer a partially elastomeric character to the resulting material. Huang et al. [92] studied some sequential IPNs of PDMS and polymethacrylate and varied the ester functionalities the polysiloxane network was swollen with MMA (methyl methacrylate), EMA (ethyl methacrylate) or BuMA (butyl methacrylate). Using DMA the authors determined that the more sterically hindered the substituent, the broader the damping zone of the IPN (Table 2). This damping zone broadness was also found to be dependant on the PDMS content, and atomic force microscopy (AFM) was used to observe the co-continuity of the IPN. 

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... 

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