摘要:

AbstractColloidal particles of three‐block copolymers polycaprolactam‐block‐polystyrene‐block‐polycaprolactam, formed in a solvent mixture toluene/2,2,3,3‐tetrafluoropropanol as a good solvent of polycaprolactam, were studied by static and dynamic light scattering and transmission electron microscopy. Two kinds of spherical multimolecular particles differing in size were found in the solution. The smaller particles containing tens of copolymer molecules were interpreted as regular copolymer micelles, and the larger particles formed from thousands of copolymer molecules were interpreted as associates of the

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890121

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractIn order to calculate the interference effects from liquid‐crystalline block copolymers, Biswas and Blackwell have presented an elegant matrix method. For the cases where an analogous, analytical approach can be made, we show that the matrix method leads to the same result as the analytical method. In addition to the conventional reciprocal lattice with reciprocal lattice points ath2π/〈c〉, where 〈c〉 is the average periodicity, one has to consider three further reciprocal lattices with reciprocal lattice pointsh′2π/cA,h″2π/cB, andh″′2π/(cB+cB).cBandcBare the lengths of the comonomer units. This method will be illustrated by model calculations forp‐benzoate/biphenyl‐4,4′‐diylisophthalate copolyestersPoly[(isophthalic acid‐alt‐biphenyl‐4,4′‐diol)‐co‐4‐hydroxybenzoic acid].. Further, interesting possibilities

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890122

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe Gaussian network theory of Kuhn and Grün neglects the limited contour length of network chains connecting neighbouring crosslinking points. Therefore, in the unstrained material Treloar replaces Gaussian network chain statistics by a sperical shell distribution neglecting the random walk behaviour of chain segments. We try to overcome this discrepancy in the present paper. Starting from Gaussian end‐to‐end distance statistics in the unstrained material we calculate the strain dependent amount and orientation of fully extended chains in strained samples. Fully extended chains are supposed to behave as stiff rods during further elongation. Thus, we take into account randomly coiled and fully extended chains simultaneously. We, therefore, have to replace the conventional assumption of linear affine deformation by a more complex relation, i. e. by a geometrically averaged affine deformation. This is connected with a model strain ratio differing from the macroscopic strain. The model ratio refers to the orientation behaviour of the end‐to‐end vectors, which, in the case of already fully extended network chains, hardly contribute to the macroscopic elongation of the sample. The calculation leads to a bimodal orientation function. The orientation factor is similar to that which follows from the conventional theory, whereas the entropic retractive force deviates from the conventiona

ISSN:0025-116X    

DOI:10.1002/macp.1988.021890123

出版商:Hüthig&Wepf Verlag    

年代:1988

数据来源: WILEY