Physical aging blends Poly

Physical Aging of Poly(phenylene Ether)/Polystyrene Blends. 185... 

Arrighi, V., Cowie, J. M. G., Ferguson, R., McEwen, 1. J., McGonigle, E.-A., Pethrick, R. A., and Princi, E., Physical ageing in poly(4-hydroxy styrene)/poly(vinyl methyl ether) blends, Polym. Int., 55, 749-756 (2006). 

Mijovic, J., and Kwei, T. K., Physical ageing in poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) blends II. Enthalpy relaxation, Polym. Eng. ScL, 29,1604—1610 (1989). 

Sayin B, CaliaS, Marangoz AS (2006) Clinical implantation of vancomycin microspheres in blend with human/rabbit bone grafts to infected bone defects. Microencapsul 5 553-556 Scandola M, CeccoruUi G, Pizzoli M (1989) The physical aging of poly(D-[beta]-hydroxybutyrate). Macromol Chem Rapid Commim 10 47-50... 

Vernel, )., Rychwalski, R.W., Pelisek, V., Saha, P., Schmidt, M.K, and Maurer, F.H.J. (1999) Physical aging in poly (ethylene oxide) /atactic-poly(methyl methacrylate) blends. Thermoddm. Acta, 342, 115. 

Mijovic, J., Devine, S.T., and Ho, T. (1990) Physical aging in poly(mefhyl methacrylate) /poly (styrene-co-acrylonitrile) blends. Part I stress relaxation. J. Appl. Polym. Sci., 39,... 

C.G. Robertson, G.L. Wilkes, Physical aging behavior of miscible blends ofpoly(methyl methacrylate) and poly(styrene-co-acrylonitrile). Polymer 42 (2001) 1581-1589. 

Polybutadiene-PMMA (80 20) core-shell particles of 0.18 pm diameter have been shown to reduce the rate of embrittlement of polycarbonate degraded by physical ageing just below the glass transition temperature [132]. The unmodified polycarbonate became brittle (as assessed by 80% of specimens showing brittle fracture) after 5 h at 135 °C in air, whereas a blend containing 10 wt% of the core-shell particles withstood these conditions for 800 h before embrittlement. By using more thermally stable particles with a poly(n-butyl acrylate) core, embrittlement was further delayed to times greater than 4500 h,... 

The objective of this investigation is to describe the effect of physical aging on the molecular motion of the membranes of PMSP and poly(l-trimethyl-l-propyne-co-1-phenyl-1-propyne) [poly(TMSP-co-PP] and blend polymer of PMSP with poly(l-phenyl-1-propyne) (PPP). 

The first comprehensive study of physical aging in a miscible blend system using enthalpy relaxation was reported by Cowie and Ferguson (1989) who followed the enthalpic relaxatirm in a series of blends of PS and poly(vinyl methyl ether), PVME. ComparisOTi of the blend behavior with that of the two components by analyzing the data oti the basis of both the P-M and C-F models led to the conclusions that the blends aged more slowly than PVME when aging was carried... 

H. Wang, X. Sun, and P. Seib, Properties of poly (lactic acid) blends with Vcuious starches is affected by physical aging. J. Appl. Polym. Sci. 90(13), 3683-3689 (2003). 

The transport properties of incompatible blends of poly(ethylene terephthalate) (PET) and a blend composed of 40mol% PET and 60mol% Rodrun 3000 were investigated, using dichloromethane as permeant [68]. Blends submitted to physical aging showed a decrease in permeability of a proportion that was increased in line with the amount of LC phase present, and by a larger contribution that was derived from the polymeric matrix. This decrease in permeability was essentially attributed to a lowering of sorption, as the diffusional behavior of the different samples was the same. 

In this paper, physical aging of gas permeability properties of PTMSP is described using the dud mode sorption and transport model, lliis model is also used to rationalize the increase in stability of gas permeation properties as a result of blending PTMSP with poly(tert-butyl acetylene) (PTBA). 

Cowie, J.M.G., McEwen, I.J., and Matsuda, S. (1998) Stress relaxation and physical ageing in a blend of poly(styrene-co-acrylonitrile) and poly(methyl methacrylate)./. Chem. Soc., Faraday Trans., 94, 3481. 

Robertson, C.G. and Wilkes, G.L. (2000) Physical aging behavior of miscible blends containing atactic polystyrene and poly(2,6-dimethyl-l,4-phenylene oxide). Pdymer, 41, 9191. 

Cowie, J.M.G. and Ferguson. R. (1989) Physical ageing studies in polymer blends. 2. Enthalpy relaxation as a function of ageing temperature in a poly (vinyl methyl ether)/polystyrene blend. Macromolecules, 22, 2312. 

DSC curves of physical aged poly (lactic acid) (PLA)/starch/ methylenediphenyl diisocyanate (MDI) (55/45/0.1) blends (Wang eta/., 2003). 

The materials analyzed were blends of polystyrene (PS) and poly(vinyl methyl ether) (PVME) in various ratios. The two components are miscible in all proportions at ambient temperature. The photooxidation mechanisms of the homo-polymers PS and PVME have been studied previously [4,7,8]. PVME has been shown to be much more sensitive to oxidation than PS and the rate of photooxidation of PVME was found to be approximately 10 times higher than that of PS. The photoproducts formed were identified by spectroscopy combined with chemical and physical treatments. The rate of oxidation of each component in the blend has been compared with the oxidation rate of the homopolymers studied separately. Because photooxidative aging induces modifications of the surface aspect of the material, the spectroscopic analysis of the photochemical behavior of the blend has been completed by an analysis of the surface of the samples by atomic force microscopy (AFM). A tentative correlation between the evolution of the roughness measured by AFM and the chemical changes occurring in the PVME-PS samples throughout irradiation is presented. 

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