Partially miscible EVOH/copolyamide‐6/6.9 blends: The effect of stretching on the structure

Binary blends of random copolymers, ethylene‐vinyl‐alcohol (EVOH) consisting of 38 mol % ethylene and Copolyamide‐6/6.9 with an approximate 1 : 1 comonomer ratio, were prepared via blown‐film extrusion and uniaxial stretching. The anisotropy induced by the uniaxial deformation of the polymer blends was characterized by X‐ray diffraction and birefringence measurements. The stretched films also were investigated via oxygen permeability. The results showed a sharp decrease in the apparent crystallite size throughout the entire composition range in comparison to the blown films. However, the order perceived within the amorphous phase in the EVOH‐rich blends increased (decrease in oxygen permeability), whereas in the copolyamide‐rich blends, orientation resulted in a decrease in the amorphous phase order (increase in permeability). Apparently, orientation destroyed the amorphous interpolymer complex. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 813–822, 2000     

Thermotropic copolyamides from triethyleneglycol bis(4-carboxyphenyl)ether and two kinds of aromatic diamines

Thermotropic copolyamides were prepared from triethyleneglycol bis(4-carboxy-phenyl)ether (PEG₃) and two types of diamines, substituted p-phenylenediamines and 4,4'-diaminodiphenyls, and depression of melting point and isotropization temperature of the copolymers produced were measured as a function of diamine combination. The depression was not practically observed by the combinations of homologous diamines with several kinds and numbers of substituents, but significant by those of the diamines with different lengths of the mesogenic segments, and by the molar ratios of the diamines employed. The effect was discussed in terms of deviation of interchain hydrogen bonding between amide bonds in the main chain. © 1994 John Wiley & Sons, Inc.     

Synthesis of multifunctional copolyamides with both cyclobutane ring and conjugated double bond in the main chain

Copolyamides 1,9 , and 10 containing both cyclobutane rings and conjugated double bonds in the main chain were synthesized by polycondensation of 1,3-di(4-piperidyl)propane (DPP) with β-truxinate (β-BNPT), with di(p-nitrophenyl) p-phenylenebis(acrylate) (p-NPDA), with di(p-nitrophenyl) p-phenylenebis (α-cyanoacrylate) (p-NPDC), and with di(p-nitrophenyl) p-phenylenebis (α-cyanobutadienecarboxylate) (p-NPDCB) in aprotic polar solvents at room temperature, respectively. Reduced viscosity of copolyamide 1 was strongly affected by the reaction process, the molar ratio of two ester monomers, and reaction time. The copolyamide 1 with the highest viscosity was prepared by the reaction of DPP with 70–50 mol % of β-BNPT for 24 h followed by the polycondensation of the resulting precursor with 30–50 mol % of p-NPDA for 24–96 h. Although copolyamide 9 with high viscosity was not obtained by the polycondensation with β-BNPT and p-NPDC, copolyamide 10 with relatively high viscosity was obtained by the reaction with β-BNPT and p-NPDCB under the same conditions applied for the synthesis of copolyamide 1 . The solubility of copolyamides 1,9 , and 10 decreased gradually with increasing p-NPDA, p-NPDC, and p-NPDCB units in the copolymers. Furthermore, it was found that copolyamides 1,9 , and 10 crosslinked upon irradiation with 313 or 365 nm light, and these copolyamides also decomposed upon irradiation with 254 nm light. That is, the photochemical property of these copolyamides can be controlled by the selection of wavelength of the photoirradiation.     

缩聚的溶剂体系对芳香－脂肪族共聚酰胺序列结构的影响

本文研究了以对苯二甲酰氯、对苯二胺和乙二胺三元共缩聚物为代表的芳－脂族共聚酰胺低温溶液缩聚中的溶剂、助溶剂（盐）和酸吸收剂等对共聚酰胺链序列结构参数－无规度（Ｂ）和数均序列长度（Ｌ）－的影响．