Stress-Induced Phase Transformation in Poly vinylidene fluoride

2 Stress-Induced Phase Transformation in Poly(vinylidene fluoride) 

The observed decrease in intensity is simply a consequence of the significant film thickness reduction in the elongated sample. 

Another example for the use of polarized radiation in imaging studies is the analysis of PVDF films, which have been uniaxially elongated at different temperatures [64]. 

In order to monitor the transformation of the 11(a) into the I(P) modification, the structural absorbance of the 975 cm band (yj(CH2)-F vibration) 

The diffusion of small molecules into polymeric materials is important for many areas of application, for example, food packaging or protective clothing. Polyamides absorb small molecules such as water and alcohols, and this process is accompanied by a change of the melting and glass-transition temperatures [67] and also has a strong influence on their mechanical [68] and electrical [69] 

Case II transport occurs when the sorption is entirely controlled by stress-induced relaxations taking place at a sharp boundary separating an outer swollen shell, essentially at equilibrium penetrant concentration, from an unpenetrated glassy core. Ideally, this sharp boundary moves through the polymer at a constant velocity during case II transport. Supercase II transport occurs when the velocity of the case II sorption boundary is sufficiently slow so that a Fickian tail may develop ahead of the sorption discontinuity [70]. 

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