Poly dynamic mechanical analysis

The thermal glass-transition temperatures of poly(vinyl acetal)s can be determined by dynamic mechanical analysis, differential scanning calorimetry, and nmr techniques (31). The thermal glass-transition temperature of poly(vinyl acetal) resins prepared from aliphatic aldehydes can be estimated from empirical relationships such as equation 1 where OH and OAc are the weight percent of vinyl alcohol and vinyl acetate units and C is the number of carbons in the chain derived from the aldehyde. The symbols with subscripts are the corresponding values for a standard (s) resin with known parameters (32). The formula accurately predicts that resin T increases as vinyl alcohol content increases, and decreases as vinyl acetate content and aldehyde carbon chain length increases. 

A reversible succession of order-order and order-disorder transition was observed for a poly(ethylene-a/f-propylene)- -poly(ethylene-co-butylene)-b-polystyrene terpolymer, which shows at room temperature non-hexagonally packed PS cylinders. Upon heating, this system reorganizes to a hexagonally packed one, and at higher temperatures dynamic-mechanical analysis indicates the transition to the disordered state [73],... 

Crosslinked polymer networks formed from multifunctional acrylates are completely insoluble. Consequently, solid-state nuclear magnetic resonance (NMR) spectroscopy becomes an attractive method to determine the degree of crosslinking of such polymers (1-4). Solid-state NMR spectroscopy has been used to study the homopolymerization kinetics of various diacrylates and to distinguish between constrained and unconstrained, or unreacted double bonds in polymers (5,6). Solid-state NMR techniques can also be used to determine the domain sizes of different polymer phases and to determine the presence of microgels within a poly multiacrylate sample (7). The results of solid-state NMR experiments have also been correlated to dynamic mechanical analysis measurements of the glass transition (1,8,9) of various polydiacrylates. 

Wilkes and coworkers studied polyrotaxanes derived from self-assembly of a polyurethane bearing paraquat moieties and BPP34C10 [130b]. The polyurethanes contained soft (poly(tetramethylene oxide)) and hard (paraquat ionene) segments. Interestingly, dynamic mechanical analysis indicated that polyrotaxanes had higher rubbery plateau moduli than the corresponding backbones. Thermal analysis revealed that the stability was enhanced by the formation of the polyrotaxanes. 

A series of poly(cycloalkyl methacrylates) has been investigated by dynamic mechanical analysis and solid-state 13 C NMR in order to characterise the... 

The approach developed in this paper, combining on the one side experimental techniques (dynamic mechanical analysis, dielectric relaxation, solid-state 1H, 2H and 13C NMR on nuclei at natural abundance or through specific labelling), and on the other side atomistic modelling, allows one to reach quite a detailed description of the motions involved in the solid-state transitions of amorphous polymers. Bisphenol A polycarbonate, poly(methyl methacrylate) and its maleimide and glutarimide copolymers give perfect illustrations of the level of detail that can be achieved. 

Abbreviations y x AFM AIBN BuMA Ca DCP DMA DMS DSC EGDMA EMA EPDM FT-IR HDPE HTV IPN LDPE LLDPE MA MAA MDI MMA PA PAC PB PBT PBuMA PDMS PDMS-NH2 interfacial tension viscosity ratio atomic force microscopy 2,2 -azobis(isobutyronitrile) butyl methacrylate capillary number dicumyl peroxide dynamic mechanical analysis dynamic mechanical spectroscopy differential scanning calorimetry ethylene glycol dimethacrylate ethyl methacrylate ethylene-propylene-diene rubber Fourier transform-infra-red high density polyethylene high temperature vulcanization interpenetrating polymer network low density polyethylene linear low density polyethylene maleic anhydride methacrylic acid 4,4 -diphenylmethanediisocyanate methyl methacrylate poly( amide) poly( acrylate) poly(butadiene) poly(butylene terephtalate) poly(butyl methacrylate) poly(dimethylsiloxane) amino-terminated poly(dimethylsiloxane)... 

STUDY OF ADDITIVE COMPATIBILITY WITH POLY(VINYL CHLORIDE). I. DYNAMIC MECHANICAL ANALYSIS (DMA) OF IMPACT MODIFIED RIGID PVC CONTAINING ESTER LUBRICANTS... 

Fig. 9. Dynamic mechanical analysis plots of tan 5 against temperature for chlorinated polyethylene (52 % Cl) (4) and blends with poly(butyl acrylate) containing (3) 84.7% PBA, (2) 64.1 % PBA, and (1) 46.1 % PBA. The inset shows a plot of T, against weight percent chlorinated polyethylene where there is a marked deviation from linearity indicative of a specific interaction...

Fig. 3. Dynamic mechanical analysis of poly(amic alkyl ester). Sample heated to 300 °C and held (1 h), cooled and rerun to 450 °C...

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