Polymethyl methacrylate glass transition temperature

The latest vinylferrocene monomer / -C5H4CH202CC(CH3) = CH2 rj -C5H4CH = C(CN)C02Et Fe 15 that undergoes radical polymerization has been prepared as shown in Scheme 10-3 [17] Copolymerization of the monomer with methyl methacrylate produced copolymer 16, via radical initiation using AIBN in benzene. The ethyl a-cyanoacrylate moiety on the ferrocene remained intact through the polymerization process. The thermal behavior of 16 was similar to that of polymethyl methacrylate glass transition temperature, 7 120 °C, melt transition... 

The acrylic plastics use the term acryl such as polymethyl methacrylate (PMMA), polyacrylic acid, polymethacrytic acid, poly-R acrylate, poly-R methacrylate, polymethylacrylate, polyethylmethacrylate, and cyanoacrylate plastics. PMMA is the major and most important homopolymer in the series of acrylics with a sufficient high glass transition temperature to form useful products. Repeat units of the other types are used. Ethylacrylate repeat units form the major component in acrylate rubbers. PMMAs have high optical clarity, excellent weatherability, very broad color range, and hardest surface of any untreated thermoplastic. Chemical, thermal and impact properties are good to fair. Acrylics will fail in a brittle manner, independent of the temperature. They will suffer crazing when loaded at stress about halfway to the failure level. This effect is enhanced by the presence of solvents. 

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. 

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). 

Glass transition temperature of the components in polymethyl methacrylate/polystyrene (PMMA/PS) ( , PMMA O, PS) and polyvinyl chloride (PVC)/PS (A, PVC PS) blends. (Reproduced from Fekete, E., Foldes, E., and Pukanszky, B. 2005. Effect of molecular interactions on the miscibility and structure of polymer blends. European Polymer Journal 41 727-736 with permission from Elsevier.)... 

The supramolecular network structure formed from polymethyl methacrylate (PMMA) copolymer mixtures featuring specific multiple hydrogen-bonding interactions. (Reprinted with permission from Kuo, S. W., and Tsai, S. T. 2009. Complementary multiple hydrogen-bonding interactions increase the glass transition temperatures to PMMA copolymer mixtures. Macromolecules 42 4701-4711. Copyright 2009, American Chemical Society, USA.)... 

SMP based on miscible blends of semicrystalline polymer/amorphous polymer was reported by the Mather research group, which included semicrystalline polymer/amorphous polymer such as polylactide (PLA)/poly vinylacetate (PVAc) blend [21,22], poly(vinylidene fluoride) (PVDF)/PVAc blend [23], and PVDF/polymethyl methacrylate (PMMA) blend [23]. These polymer blends are completely miscible at all compositions with a single, sharp glass transition temperature, while crystallization of PLA or PVDF is partially maintained and the degree of crystallinity, which controls the rubbery stiffness and the elasticity, can be tuned by the blend ratios. Tg of the blends are the critical temperatures for triggering shape recovery, while the crystalline phase of the semicrystalline PLA and PVDF serves well as a physical cross-linking site for elastic deformation above Tg, while still below T ,. 

Crystallinity plays a large role in the physical behavior of polymers. The amorphous regions play perhaps an even greater role. Some amorphous polymers such as polymethyl methacrylate (PMMA) are stiff, hard plastics at room temperature, whereas polymers such as polybutadiene are soft and flexible at room temperature. If PMMA is healed to lOS C, it will soften, and its modulus wiU be reduced by orders of magnitude. If polybutadiene is cooled at to —73 C, it will become stiff and hard. The temperature at which this hard-to-soft transformation takes place is called the glass transition temperature T. ... 

It can be seen that the temperature sensitivity drops dramatically (several decades) when T-Tg increases. The closer a polymer is to its glass transition temperature, the larger the temperature sensitivity of the viscosity. This explains why polymers whose normal process temperatures are close to their glass transition temperature exhibit a high temperature sensitivity in processing. Examples are polystyrene, polyvinylchloride, and polymethyl methacrylate. In general, polymers that are processed considerably above their glass transition temperature (more than 150°C above Tg) show a relatively small temperature sensitivity. Examples are polyethylene, polypropylene, and polyamide. 

First, studying different polar polymers [258,263-265] such as poly(ethylene oxide) (PEO), polyvinyUdene fluoride (PVdF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and polyvinyl chloride (PVC) in order to enhance the ionic conductivity of the SPEs. PEO has been foimd to be the most successful host material for SPEs due to its low glass transition temperature (-60 °C) [266]. Second, increasing the niunber of charge carriers by use of highly dissociable salts, and increasing the salt concentration. Third, suppressing the crystallization of the polymer chains reduces the conductivity at room temperature ([Pg.1101]

This involves the use of the Charlesby-Pinner (CP) (22-24) treatment which describes the determination of the gel firaction of the polymer as a function of radiation dose. Figures 4(a) and 4(b) illustrate that pofymers with structures as those shown for Polymers 1 and 2 crosslink when exposed to Co radiation. Polymer 1 has been synthesized with approximately 7 % of the allylic substituent, while the thesis of polymer 2 allowed for 3-4% of the same allylic group. Glass transition temperatures for these pofymers are not quite that of conventional resists such as polymethyl methacrylate (> 100°C), and it is speculated that as allyl content is ino-eased, Tgs will decrease slight. ... 

The current interest is the examination of the consequences of fiee-volume theory on the effect of the solvent size on diffusional behavior, and the behavior of the diffusion process near the glass transition. Clearly, these two problems are interrelated. The experimental data needed to investigate both are accurate diffu-sivity-temperature data for a series of solvents that covers a wide range of molecular sizes. The series of solvents used should include solvents of large molecular size, incapable of segmental motion. Some recent work is reported hoe using polymethyl methacrylate, an amorphous polymer that can be studied over a wide temperature range. 

In Chapter 5 we cited dynamic mechanical relaxation data for polymethyl methacrylate (PMMA). There it was shown that PMMA possesses two mechanical relaxation regions over the temperature range - 50° to 160°C at low frequencies. These were labeled a for the relaxation accompanying the glass transition and / for a secondary relaxation that has generally been associated with motions of the ester side group. PMMA has a predominantly nonpolar... 

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