Polyalkyl acrylates

The compatibility of polymers can be related to their 5 values. Thus various polyolefins are compatible, and many of the polyalkyl acrylates and alkyl methacrylates are also compatible with each other (see Tables 8.1, 8.2). 

Several flexible polymers, such as natural rubber (NR) synthetic rubber (SR) polyalkyl acrylates copolymers of acrylonitrile, butadiene, and styrene, (ABS) and polyvinyl alkyl ethers, have been used to improve the impact resistance of PS and PVC. PS and copolymers of ethylene and propylene have been used to increase the ductility of polyphenylene oxide (PPO) and nylon 66, respectively. The mechanical properties of several other engineering plastics have been improved by blending them with thermoplastics. 

They are atactic amorphous polymers which have good light transparency (92%) and yield transparent moldings and films. As was noted for polyalkyl acrylates, the solubility parameters decrease as the size of the alkyl groups increases. The flexibility also increases as one goes from polymethyl methacrylate (PMMA) to polyaryl methacrylate and then decreases as the size of the alkyl group is further increased. 

The presence of two substituents on every alternate carbon atom restricts chain mobility, so polyalkyl methacrylates are less flexible than the corresponding polyalkyl acrylates. Also, the presence of an alpha alkyl group increases (compared with the corresponding polyalkyl acrylates) the stability of polyalkyl methacrylates to light and chemical degradation,... 

Unlike the polyalkyl acrylates, which are thermally degraded by random chain scission, polyalkyl methacrylates unzip when heated, and excellent yields of the monomers are produced when the polymers of the lower homologues are heated. When higher homologues are heated, there is also some thermal degradation of the alkyl substituents. 

Fig. 26. Plot of area ratios for the cote Levels versus number of carbons on the alkyl group of a series of polyalkyl acrylates. (These have been corrected for differences in cross section and instrumental sensitivity.)...

Whilst for the polymer samples discussed above, structure and bonding in the outermost few tens of Angstroms sampled by ESCA corresponds to that in the bulk this is not always the case. For example Fig. 29 shows the ESCA spectra for a further series of polyalkyl acrylates. 

Fjg. 30. (a) Plot of the intensity ratios for the individual components of the Ois levels and also the 0ls/02s ratios for a series of polyalkyl acrylates. 

The benzenoid C-l resonance of styrene units in acrylonitrile-styrene copolymers is particularly sensitive to the sequence of the chain relative configurations of triad sequences can be determined by quantitative evaluation of carbon-13 signals [524], Micro-structures of other vinyl polymers such as polystyrene [525], polypropylene oxide [526], and polyalkyl acrylates [527] have also been investigated by 13C NMR. 

Platelet Activation by Polyalkyl Acrylates and Methacrylates The Role of Surface-Bound Fibrinogen... 

Figure K Structure of polyalkyl acrylates and methacrylates. Polymers were synthesized by free radical polymerization Initiated by exposing alkyl acrylate and methacrylate monomers to high doses ( 10 Mev) of ionizing radiation using a Van de Graff accelerator. Polymers were separated from unreacted monomer by precipitating in methyl alcohol and redissolving in chloroform. Purified polymers were dissolved in chloroform for use in coating glass beads columns and glass cover slips.

Figure 2. Platelet retention by polyalkyl acrylates and by polyalkyl methacrylates plotted vs length of the alkyl side chain (A) or glass transition temperature, Tg (B). (Replotted from data in Fig. 3 of Ref. 17.)...

TABLE 1. Reactivity of Polyalkyl Acrylate and Methacyrylate Polymers ... 

Emulsions of polyvinyl acetate and polyalkyl acrylates have been used as tub caulking compositions, spackling compounds and as building sealants.22 Acrylic sealants which harden in the presence of powdered iron or copper meet Federal Specifications TT-S-00230C. 27 Liquid monomers, such as polyethylene glycol dimethacrylate and butyl alpha—cyanoacrylate have been used as room temperature curing sealants.22 22. 

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