METHYLACRYLATE COPOLYMER

Vinyl alcohol/acrylic acid copolymers. Vinyl alcohol/sodium acrylate copolymers were obtained by hydrolysis of vinyl acetate/ methylacrylate copolymers with alkaline solution. The vinyl alcohol/sodium acrylate copolymers obtained are insoluble in water, although they are not crosslinked with crosslinking monomer. This is because of crystal structure of vinyl alcohol moieties in the copolymers. Therefore, the vinyl alcohol/sodium acrylate copolymers have higher mechanical strength than crosslinked poly(sodium acrylates) in water. 

SP. (Chevron] Ethylene-methylacrylate copolymer for film, coating, laminating. 

The immiscible blends with <5 wt% of either component were introduced first (e.g., POM with PA or PARA) before adequate methods of compatibiUza-tion were developed. Owing to the crystalline nature of these resins, the blends should also be impact modified. It is noteworthy that in blends of semicrystalline resins the total crystallinity tends to increase [Nadkami and Jog, 1991]. The compatibihzation and impact modification are often accomplished using a multi-polymer. For example, POM/PA-66 blends have been modified by adding either an ethylene-methylacrylate copolymer (EMAC), PEG [Kohan, 1982], or a melamine-derivative dispersant [Tsukahara and Niino, 1992, 1994]. 

EMAc ethylene methylacrylate copolymer PMMA poly(methylmethacrylate)... 

A Laser Photoacoustic Technique (LPAT) has been developed to detect and monitor outdoor photo-oxldatlon In Ethylene Methylacrylate copolymer (EMA). LPAT has been used to demonstrate that the Controlled Environmental Reactor (CER), an accelerated testing chamber that was developed at JPL, Is a valid accelerated simulator of the real-time outdoor photooxldatlon with respect to the rate of formation of the hydroxyl functional group. 

Samples of Ethylene/Methylacrylate copolymer (EMA) were obtained from Gulf Oil Company (TD938) and repreclpltated from hot cyclohexane. The purified samples were then compression molded Into thin films (25-50 urn). FT-IR spectra were recorded on a Dlgllab FT-IR Spectrophotometer Model FTS 15. 

Fig. 2.5 Impact of the copolymer composition on the solubility of ethylene/methylacrylate-copolymers (EMA) in supercritical carbon dioxide. Subscripts Indicate the amount of methylacrylate monomers in the copolymer in mol%. Experimental data from [6].

There is a paucity of data for the standard small scale oxygen index and UL 94 tests [37], but what little there is strongly suggests that nano-clays are not very good in these tests at the normal loadings (up to 10%) that they are used at. Thus, 7% of a nano-clay was found to have little effect on the oxygen index of an ethylene methylacrylate copolymer [38]. This may he the reason why interest in this area was slow to develop. Nearly all of the available data is with the more recently developed cone calorimeter test, where excellent results are achievable. 

Finally, the most recent promising classes in the field of SPEs are the zwitter-ions, identified as Li ion dissociation enhancers , namely ionic liquids where both the anion and cation are immobilized on the same structure. If dispersed into proper PEO-like polymers, the zwitterionic compounds may increase the ionic conductivity of the polymer electrolytes [80]. In case of addition of l-butylimidazolium-3-(n-butanesulphonate) dissociator to Lithium methylacrylate copolymers, for instance, the ionic conductivity achieves a maximum close to 0.6 m cm at 30 °C, in presence of a Li" mole fraction in the copolymer of about 0.050. 

Table 7.16 contains the copolymerisation parameters of acrylonitrile-methylacrylate copolymers containing between 0.36 and 0.88 mole fraction of acrylonitrile (i.e., F ) for various monomer feed ratios and indicate that a knowledge of mole fractions (F) and reactivity ratios (r) enables prediction to be made, not only of average mole ratios but also of average number of sequences of monomer units per length of polymer and the average sequence length of each monomer. 

Table 7.16 Copolymerisation parameters of acrylonitrile-methylacrylate copolymers determined by C-NMR spectroscopy ...

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