Polymethyl methacrylate structure

Scheme 1 Schematic structure of graft block copolymer [51] TTTm = polymethyl methacrylate segment w AA = po-lydimethylsiloxane segment.

The lack of solvent separated pairs raises the question whether some alternative mode of solvation should be considered. The ester group of the penultimate unit of the polymer, or the one preceeding it, could act as a solvating agent. The idea of intramolecular solvation was proposed by several workers in the field 37) and it is supported by the results of nmr studies of polymethyl methacrylate formed under various experimental conditions 38). Hypothetical structures such as those depicted below were proposed 39 h... 

Another differential reaction is copolymerization. An equi-molar mixture of styrene and methyl methacrylate gives copolymers of different composition depending on the initiator. The radical chains started by benzoyl peroxide are 51 % polystyrene, the cationic chains from stannic chloride or boron trifluoride etherate are 100% polystyrene, and the anionic chains from sodium or potassium are more than 99 % polymethyl methacrylate.444 The radicals attack either monomer indiscriminately, the carbanions prefer methyl methacrylate and the carbonium ions prefer styrene. As can be seen from the data of Table XIV, the reactivity of a radical varies considerably with its structure, and it is worth considering whether this variability would be enough to make a radical derived from sodium or potassium give 99 % polymethyl methacrylate.446 If so, the alkali metal intitiated polymerization would not need to be a carbanionic chain reaction. However, the polymer initiated by triphenylmethyl sodium is also about 99% polymethyl methacrylate, whereas tert-butyl peroxide and >-chlorobenzoyl peroxide give 49 to 51 % styrene in the initial polymer.445... 

Polymethyl methacrylate (PMMA) degrades under irradiation and becomes more soluble due to main chain scission. The degradation can be greatly reduced by the addition of 10% of various additives, such as aniline, thiourea, or benzoquinone. PMMA is an example of a nongelling polymer it does not form a three-dimensional network structure under irradiation. ... 

Shirakashi, K., K. Ishikawa, and K. Miyasaka The fine structure of cellulose on cellulose-polymethyl methacrylate copolymerization. Part I. J. Soc. Text, and Cell. Ind. (Japan) 19, 178 (1963) Part II. Ibid 19,182 (1963). 

FIGURE 15.4 (a) Thermal gravimetric analysis for polyiniethyl methacrylate) (FMMA) and IMMA/AlaOs mixture in air atmosphere. Taken finn Sun et al. [28]. (b) Fourier transfiarm infrared (FTIR) peak intensity versus pyrolysis temperature for polyimethyl methacrylate) (PMMA) in air atmosidiere. Taken from Sun et al. [28]. (c) Fourier transform infrared (FTIR) peak intensity versus pyrolysis temperature for poly(methyl methacrylate) (PMMA)/Al203 mixture in air atmosphere. Taken flam Sun et al. [28]. (d) Structure of polymethyl methacrylate (PMMA). Reprinted by permission of the American Ceramic Society. 

X-ray and neutron diffraction measurements on polyion hydration give the number of water molecules involved per repeat group in the structures. About one water molecule per repeat group is the result for polymethyl methacrylate. The results of hydration for a variety of proteins are given in Table 2.31. 

Water in a never-dried fresh-cut tree, when exchanged with a series of organic solvents, could be replaced with H- (or tritium-) labeled MMA (42). After polymerization and the use of autoradiography the H-labeled MMA was located in the cell wall and compound middle lamella. The polymer (polymethyl methacrylate) labeled with was removed from the capillaries and void spaces in the wood by solvent extraction, but the labeled polymethyl methacrylate in the wood structure remained. The same wood, after oven drying, was treated with the H-labeled monomer by using the full cell method. Again, by autoradiography, the H-labeled polymethyl methacrylate was located in the capillaries and void spaces. After solvent extraction of the poly methyl methacrylate no labeled polymer... 

In this study, we discussed the graded and miscible blend of polyvinyl chloride(PVC)/ polymethacrylate(polymethyl methacrylate(PMMA) or polyhexyl methacrylate(PHMA)) by a dissolution-diffusion method, and characterized graded structures of the blends by measuring FTIR spectra and Raman microscopic spectra, and thermal behaviors around the glass transition temperature(Tg) by DSC method, or by SEM-EDX observation. Finally, we measured several types of mechanical properties and thermal shock resistance of the graded polymer blends. 

This chapter discusses the independent determination of parameters for a cluster entanglement network enabling the accurate description of the experimental data on the molecular orientation in polymethyl methacrylate. This confirms the validity of the earlier proposed structural model for the polymer amorphous state [1, 2]. 

The relative effects of temperature rises on different plastic materials depend on the structure of each material and, particularly, whether it is crystalline or amorphous. If a plastic is largely amorphous (e.g., polymethyl methacrylate, polystyrene), then it is the glass transition temperature (Tg) which will determine the maximum service temperature, since above Tg the material passes into the rubbery region (see Figure 1.19). 

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