Poly dynamic mechanical properties

The presence of three oxyethylene units in the spacer of PTEB slows down the crystallization from the meso-phase, which is a very rapid process in the analogous polybibenzoate with an all-methylene spacer, P8MB [13]. Other effects of the presence of ether groups in the spacer are the change from a monotropic behavior in P8MB to an enantiotropic one in PTEB, as well as the reduction in the glass transition temperature. This rather interesting behavior led us to perform a detailed study of the dynamic mechanical properties of copolymers of these two poly bibenzoates [41]. 

Lai MF, Li J, Liu JJ (2005) Thermal and dynamic mechanical properties of poly(propylene carbonate). J Therm Anal Calorim 82 293-298... 

Langley, N.R., Ferry, J.D. Dynamic mechanical properties of crosslinked rubbers. VI. Poly(dimethylsiloxane) networks. Macromolecules 1, 353-358 (1968). 

Beckham and coworkers studied the dynamic mechanical properties of poly(urethane-crown ether rotaxane)s [138]. No difference was observed between the backbone and polyrotaxane, probably because of the low min value (0.02). However, 13C solid-state NMR detected die presence of the crown ether as a mobile structure at room temperature. The same observation was seen in polyrotaxanes with ether sulfone and ether ketone backbones (77-80) [114]. Although no detailed properties were reported, the detection of the liquid-like crown ether provided very important information in terms of mechanical properties, because these properties are the result of molecular response to external forces. For example, mobile crown ethers can play the role of plasticizers and thus improve impact strength. 

Ma, X., Sauer, J. A., and Hara, M. (1995). Poly(methyl methacrylate) based ionomers. 1. dynamic mechanical properties and morphology. Macromolecules 28, 3953-3962. 

Heijboer [28] has reported the dynamic mechanical properties of poly(nethacrylate)s with different size of the saturated ring as side chain. The y relaxation in these polymers is attributed to a conformational transition in the saturated ring. In the case of poly(cyclohexyl methacrylate), the transition is between the two chair conformations in the cyclohexyl ring. However, this type of internal motion in hindered by rather high intramolecular barriers, which can reach about 11 kcal mol-1. 

ABA copolymers poly(methyl methacrylate)-polyisoprene-poly(methyl methacrylate) having polyisoprene with a high vinyl content as central block have been synthetized by Cole et al. 2I°. Dynamic mechanical properties of films of these ABA copolymers have been studied as a function of the copolymer composition, the temperature and the nature of the solvent (carbon tetrachloride, toluene, ethyl acetate, methylethyl ketone, dioxane) used for film preparation210. ... 

Recently, the dynamic mechanical properties of the resins cured with a series of linear poly anhydrides having the structures shown in Table 5 were studied by Ramon41 . The dynamic mechanical properties are very similar to those of the resins cured with diamine hardeners as shown in Fig. 10. The relationships between the number of CH2 groups n and Tg Eire shown in Fig. 8. Tg drops rapidly below that of an alkyldiamine-cured resin as n increases. This is considered reasonable because, compared with the hardener.unit in an amine-cured resin, the acid anhydride segment existing in the main chain of the anhydride-cured resin is twice as long. 

Dynamic Mechanical Properties of Poly(tetramethylene ether) Glycol Polyurethanes... 

Dynamic mechanical properties of IPN 1, IPN 2, poly 23G and cured phenolic resol (CPR) were examined, in order to investigate IPN structure. 

Dynamic Mechanical Properties of Poly-n-Butyl Methacrylate. J. CoUoid Sci. 12, 327-341 (1957). 

Stern, D. M., J. W. Berge, S. F. Kurath, C. Sakoonkim, and J. D. Ferry Dynamic mechanical properties of concentrated solutions of poly-(methyl methacrylate) in diethyl phthalate. J. Colloid Sci. 17, 409 (1962). 

The results of a study of the relation between the oriented structure and drawn poly(e-caprolactone) specimens including CaCO particles, their dynamic mechanical properties and line shape analyses of CP MAS NMR spectra are presented. Solid state studies of C NMR study of poly(methyl acrylate) ionomer have been reported. ... 

A polyurethane (PU)/poly(n-butyl methacrylate) (PBMA) system has been selected for an investigation of the process of phase separation in immiscible polymer mixtures. Within this system, studies are made of the XX, lx, xl, and the 11 forms. In recognition of the incompatibility of PBMA with even the oligomeric soft segment precursor of the PU, no attempt was made to equalize the rates of formation of the component linear and network polymers. Rather, a slow PU formation process is conducted at room temperature in the presence of the PBMA precursors. At suitable times, a relatively rapid photopolymerization of the PBMA precursors is carried out in the medium of the slowly polymerizing PU. The expected result is a series of polymer mixtures essentially identical in component composition and differing experimentally only in the time between the onset of PU formation and the photoinitiation of the acrylic. This report focuses on the dynamic mechanical properties cf these materials and the morphologies seen by electron microscopy. 

T. Hayashi, J. Ito, K. Mitani and Y. Mizutani, Dynamic mechanical properties and morphology of styrene-divinylbenzene copolymer/poly(vinyl chloride) systems, J. Appl. Polym. Sci., 1983, 28, 2867-2880. 

Homogeneous single-phase polyblends are very rare. Liquid-liquid phase separation of optically homogeneous polyblends of a styrene/acrylonitrile copolymer with poly (methyl methacrylate) has been studied by L. P. McMaster. A quantitative test method of the dynamic mechanical properties of multiphase polymer systems was developed by L. Bohn. He was able to demonstrate the correlation between shear modulus and gel volume of brittle polymers... 

Although the dynamic mechanical properties and the stress-strain behavior iV of block copolymers have been studied extensively, very little creep data are available on these materials (1-17). A number of block copolymers are now commercially available as thermoplastic elastomers to replace crosslinked rubber formulations and other plastics (16). For applications in which the finished object must bear loads for extended periods of time, it is important to know how these new materials compare with conventional crosslinked rubbers and more rigid plastics in dimensional stability or creep behavior. The creep of five commercial block polymers was measured as a function of temperature and molding conditions. Four of the polymers had crystalline hard blocks, and one had a glassy polystyrene hard block. The soft blocks were various kinds of elastomeric materials. The creep of the block polymers was also compared with that of a normal, crosslinked natural rubber and crystalline poly(tetra-methylene terephthalate) (PTMT). 

Landry CJT, Coltrain BK, Brady BK. In situ polymerization of tetraethoxysilane in poly (methyl methacrylate) Morphology and dynamic mechanical properties. Polymer. 1992 33(7) 1486-1495. 

Water and low temperature (20-35 C) aging influence the dynamic mechanical properties of a poly(amide-imide). At concentrations below 2 weight percent, water contributes to a low temperature relaxation between -120 and -50 C. Above 2 weight percent the water influences the beta transition. The enthalpy of activation for the beta relaxation is dependent upon aging temperature and time. Aging temperatures closer to the beta transition temperature result in higher activation enthalpies for that dispersion. 

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