Orientation factor of polypropylene film by infrared dischroism

Abstract

SynopsisThe orientation factor by infrared dichroism of polypropylene film was compared with the other orientation factors. After the correction of imperfect polarization and the suitable choice of the base line, it was found that infrared dichroism is a reliable indicator of the orientation factor. Orientation factors obtained from the 998 and 842 cm.-l bands agreed with the x-ray orientation factor, and that from the 975 cm.-l band agreed with the optical orientation factor.

Detection of necking deformation along polypropylene fibres axis at low draw ratios using multiple-beam microinterferometry

“…Experimentally when PP fibres are drawn with fast drawing, the necking deformation appears at different positions along the fibre axis at draw ratios from D ¼ 1.2 to 1.9. This is due to the excess of heating rate of necking positions than the limit of flowing temperature of the molecular chains [17,20,21]. This excess of fibre temperature results from the work done on the fibre chains during the cold-drawing process.…”

Thermal shrinkage of drawn polystyrene

“…Imperfect polarization was corrected according to our method which has been reported previously. 16 The orientation of the main chain of polymer was calculated from the dichroism of 2923 cm-' CH2 absorbance.l7J8 Both bands of 1027 and 906 cm-' were used for studying the orientation of phenyl group in side chains. ] X 100, where 10 is the length before drawing, Id is the length after drawing, 1, is the length after heat treatment, no is the birefringence before drawing, no is the birefringence before drawing n d is the birefringence after drawing, and n, is the birefringence after heat-treatment.…”

Structure and properties of uni- and biaxially oriented polypropylene films: Part I - Structural characterization

“…This conclusion is not in agreement with various results reported in the litterature, in particular with regard to the 840 and 998 cm' bands (Refs. 26,27). If IR-absorpdon is not limited to the crystalline regions, application of Eq.…”

“…26) for the determination of an average orientation function, is the 974 cm' band. The absorbance of this band was considered too strong by most participants for yielding accurate values in the case of the uniaxially drawn films ; in the biaxially drawn films its dichroism was found to be smaller than for the 1256 cm' band although the importance of this difference varied somewhat from one laboratory to another.…”