Physical aging in poly

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). 

INVESTIGATION OF GLASS FORMATION AND PHYSICAL AGEING IN POLY(ETHYLENE TEREPHTHALATE) BY FT-IR SPECTROSCOPY... 

Cangialosi, D., Boucher, V.M., Alegria, A., Colmenero, J. Free volume holes diffusion to describe physical aging in poly(mehtyl methacrylate)/silica nanocomposites. J. Chem. Phys. 135(1), 014901 (2011)... 

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,... 

J. Scot Royal, J. G. Victor, J. M. Torkelson, Photochromic and fluorescent probe studies in glassy polymer matrices. 4. Effects of physical ageing on poly(methyl methacrylate) as sensed by a size distribution of photochromic probes, Macromolecules, 25, 729-734 (1992). 

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... 

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... 

FIG. 18-11. Tensile creep compliance plotted against time with a logarithmic scale for poly(vinyl chloride) quenched from 90°C to 40° and aged for varying periods as shown up to 1000 days. Curve at right contains all points after shifts as in Fig. 18-10 (almost no vertical shift). (Struik. ) Reproduced, by permission, from Physical Aging in Amorphous Polymers and Other Materials, by L. C. a Struik, Elsevicr/North Holland Biomedical Press, 1978. 

Struik, L.C.E., Physical Aging in Amorphous Poly, and Other Mat ls, Ele-sivier, London, 1969. 

Physical Aging of Poly(4-methyl-2-pentyne). Nagai et al (12,13) and Shimomura et al. (14) reported that the gas permeability of PTMSP decreases rather dramatically with time. This phenomenon has been ascribed to three separate mechanisms (1) physical aging leading to relaxation of the enormous levels of excess free volume in the polymer, (2) contamination of the sample by sorption of pump oil vapors during permeation experiments, and (3) chemical aging due to oxidation of the double bonds in the polymer chain backbone. 

Morisato, A., He, Z., and Pinnau, I. (1999). Mixed-gas properties and physical aging of poly(4-methyl-2-pentyne). In B. D. Freeman and I. Pinnau (Eds.), Polymer Membranes for Gas and Vapor Separation Chemistry and Materials Science. ACS Symposium Series 733. American Chemical Society, Washington, DC, pp. 56-67. 

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. 

In the vicinity of glass transition, both Eqs. (47) and (48) become Eqs. (42) and (43), respectively. The calculated dependence of the physical aging rate on temperature for polystyrene (PS), poly(vinyl chloride) (PVC), and poly(vinyl acetate) (PVAc) is shown in Fig. 17. There are five parameters (e, p, f xr, 7 ) in Eqs. (23), (2), (15) and (19). We have chosen p = 1/2. ft = 1/30, and xr = 30 min for these linear polymers in our theoretical calculation. The other two parameters r. = h and Tr are listed in Table 1. The calculation reveals that the Struik exponent (p) increases from zero above 7 to a constant below Tg, and then decreases to zero at 200 K below Tg. The three polymers all show a similar type of temperature dependence of physical aging rate, which compares well with the reported observations (see Fig. 15 of Ref. 2). 

In another development, thermal analysis of POSS-containing ABA triblock methacrylate/butyl acrylate copolymers (Fig. 4) indicated the presence of two clear glass transitions in the microphase-separated system, with strong physical aging observed in samples annealed at temperatures near the Tg of the poly(methacryl-POSS) phase [122]. 

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