Polymer matrix system

In general, the release profiles from water-soluble polymer matrix systems often are modeled13,14 simply as... 

Kitchell JP, Wise DL. Poly(lactic/glycolic acid) biodegradable drug-polymer matrix systems. Methods Enzymol 1985 112 436-448. 

In a recent study, the interphases for different fiber/polymer matrix systems were investigated. By using phase imaging the differences in local mechanical property variation in the interphase of glass fiber reinforced epoxy resin (EP) and glass fiber reinforced polypropylene matrix (PP) composites could be unraveled. As shown in Fig. 3.68, the glass fiber, the interphase and the PP matrix can be differentiated based on their surface mechanical properties as assessed qualitatively by TM phase imaging. 

The pharmacodynamic performance was studied for three drug-polymer matrix systems and comparisons were made between the In vivo and the In vitro results The systems studied were (a) gentamicin In silicone rubber, (b) tetracycline In HEMA/MMA copolymers, and (c) nlrldazole In silicone rubber. In general, the In vitro models fall short of predicting the actual In vivo results accurately, even In those cases where the controlled release of the agent showed positive, desirable results In the test animals. 

Figure 9.10 Proteins are released from matrices by diffusion through constricted pores. Schematie view of a protein/hydrophobic polymer matrix system, (a) Cross-sectional views of matrices at two different loadings. At higher loadings connected clusters of pores are formed, providing continuous paths for diffusion to the surface.

Rhine, W., et ai, A new approach to achieve zero-order release kinetics from diffusion-controlled polymer matrix systems, in R.W. Baker, Controlled Release of Bioactive Materials. New York Academic Press, 1980, pp. 177-187. 

The nanocomposite PET-PEN/MMT clay was smd-ied under steady shear, instantaneous stress relaxation, and relaxation after cessation of steady flow [83]. Relaxation times of the slow mode in instantaneous stress relaxation were longer for the systems that have presumably permanent crosslinking networks (PET-PEN) or dynamic networks (PET-PEN-MMT). These results are consistent with those found in relaxation after cessation of flow (Fig. 31.4). Nanoclay addition somehow restricts the slow relaxation (due to polymer-particle interactions). The nanocomposite exhibits lower steady-state viscosity as compared to the polymer-matrix system. This is thought to be caused by polymer-polymer slipping, as revealed by the SEM observations (Fig. 31.5a and b). 

Kaunisto, E., Manicci, M., Borgquist, P., Axelsson, A., 2011. Mechanistic modelling of drug release from polymer-coated and swelling and dissolving polymer matrix systems. International Journal of Pharmaceutics 418, 54—77. 

Fibrous composites are a relatively new technology and there are too many material and structural variables to discuss fully all the details of their mechanical behaviour. Therefore, the present chapter will concentrate on certain categories of fibre reinforced composites, all with polymer matrix systems. 

SAL 13] Salert B.C.D., KRUEGER H., Baghich S.A. et al, New polymer matrix system for phosphorescent organic light-emitting diodes and the role of the small molecular co-host . Journal of Polymer Science A Polymer Chemistry, vol. 51, no. 3, pp. 601-613,2013. 

These simple models have been widely used to describe the barrier properties of polymer layered silicate nanocomposites (Yano et al, 1997 Gusev and Lusti, 2001 Lu and Mai, 2007), however, some issues like the effect of clay platelets exfoliation / intercalation / aggregation ratio and multiphase polymer matrix system (polymer blend) remain a challenging problem for barrier property modeling. 

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