Orientational behaviours of syndiotactic 1, 2 poly-butadiene samples with different crystallinity have been studied. The birefringences of the uniaxially stretched samples show negative values, and the absolute values increase when the samples are released. Crystal orientations in the stretched and released samples were examined by the X-ray diffraction method. The intrinsic birefringence in the crystalline phase was estimated as -63.2×10-3 using the bond polarizability proposed by Bunn and Vulk. Consideration about amorphous contribution to the birefringence based on the additive assumption led to a conclusion that the conformation of the structural unit in amorphous phase must change from perpendicular to parallel structure during the stretching process.
The effective thermal conductivity of the unidirectionally oriented polyester fiber assembly was measured by an experimental apparatus based on the steady comparative method using the glass plate as the standard sample. The results were discussed in terms of the theoretical analysis presented in the previous paper. The conclusions are as follows. (1) The theoretical analysis based on the structural model predicts that at any mean sample temperature, the effective thermal conductivity falls with an increase of the volumetric ratio of a fiber assembly until it reaches a minimum value at a certain volumetric ratio. The conductivity rises with further increase of the ratio. The conductivity rises with the mean sample temperature, depending upon the temperature characteristic of the radiative heat transfer in the region of the low volumetric ratio or upon that of the conductive heat transfer in the region of the high volumetric ratio. (2) The experimental results show that the effective thermal conductivity of the unidirectionally oriented polyester fiber assembly falls with the increase of the volumetric ratio, and reaches a constant value when the ratio exceeds 0.01. This tendency agrees with the theoretical prediction qualitatively. But in the region of low volumetric ratio, the experimental values are certainly larger than the theoretical ones. The experimentally observed temperature dependence of the thermal conductivity is well reproduced by the theory.
One-step grafting onto commercial poly (ethylene terephthalate) (PET) fabrics was studied by use of the emulsion which consisted of vinyl monomer, benzoyl peroxide, monochlorobenzene, emulsifier and water. Acrylic acid (AA) and methacrylic acid (MAA) were used as vinyl monomers. When a polyoxyethylene alkyl ether type nonionic surfactant was used as the emulsifier, a gum-like material deposited remarkably on the grafted PET. This material was considered to be a product formed by the association of the polycarboxylic acid with the surfactant polyoxyethylene. The formation of the gum-like material was distinctly reduced by addition of an anionic surfactant to the nonionic surfactant or by use of a nonionic-anionic surfactant instead of the nonionic surfactant. As the monomer for the grafting, the mixture of AA and MAA was examined. The mixing ratio of AA/MAA affected grafting per cent and gave the highest grafting per cent when the ratio was about 2.5/7.5(mol./mol.). Over the whole range of the mixing ratio of the two monomers, the grafting per cent of the one-step grafting was 1.5_??_3 times higher than that of the two-step grafting reported previously. Efficient graft polymerization proceeded above 80°C and the maximum grafting percent was attained by the reaction at 100_??_110°C for 1hour. The apparent activation energy of the AA/MAA (2.5/7.5) grafting was calculated as 7.9kcal./mol. The grafting was affected by pH of the grafting emulsion. With an increase in pH which was adjusted with Na2CO3, grafting per cent increased gradually to reach the maximum at pH 3.1_??_3.3 and then decreased. However, with increasing monomer concentration, increasing degree of grafting per cent became smaller. When monomer concentration was 6%, grafting per cent decreased monotonically by addition of Na2CO3. The effect of heat treatment of PET fibers on the grafting was similar to that of heat treatment of PET on the dyeability with a disperse dye. As the treating temperature rose, grafting per cent decreased gradually to reach the minimum and then, above 200°C, began to increase. From a microscopic observation of the AA/MAA grafted PET, it became clear that the surface of the grafted PET fiber was clean and grafting took place uniformly from the surface to the center of the fiber.
Poly-trans-4-γ-propoxycyclohexylamide (PPCA) was prepared and the physical properties were investigated. Trans-PPCA was obtained by polymerizing trans-4-γ-aminopropoxycyclohexane carboxylic acid which had been derived from Et-p-hydroxybenzoate. In the hydrogenation of Et-p-hydroxybenzoate using Pd-SrCO3 catalyst, the relations between the reaction condition and the composition of the resulting products were elucidated. The hydrogenation products were cis-Et-4-hydroxycyclohexane carboxylate (EHC), trans-EHC and 2-oxabicyclo (2:2:2) octane-3-one (bicyclolactone). With raising the reaction temperature (160-200°C), the yield of the bicyclolactone increased, consequently trans-EHC decreased. However, this tendency was a little depressed by increasing the pressure of H2. Isomerization behavior of cis-EHC to trans-EHC was certainly dependent upon the reaction temperature. From the results of viscometric, thermogravimetric and IR spectrometric analyses of trans-PPCA treated at 255-360°C, it was found that the thermal degradation accompanied with C-O bond scission took place at over ca. 280°C. But trans-PPCA(Tm; 245°C) was stable enough for the melt spinning condition at 255°C, and showed a high glass transition temperature of ca. 100°C and a high moisture regain of 5.5%. In order to explain the results that the value of Tg/Tm for trans-PPCA was a little higher than that expected from the two-third rule, the effects of comformation and of inversion of cyclohexylene ring on the flexibility of ether bond were considered.
By an extention of the previous method2) a theoretical study has been made of the concentration distribution for the non-steady state diffusion in repeated laminates. The laminates considered are composed of 2m repeating units of two different substrates 1 and 2. The method to obtain the concentration distribution in a laminate 1-22) has been extended for a repeated laminate 1-2-1-2…, The treatment has been given for the conditions where the diffusion coefficients are constant and Henry's law is obeyed in each phase. Several cases have been treated numerically, and the concentration distribution and sorption rate for the laminate were compared respectively with those for homogeneous membranes. Several methods to evaluate the over-all diffusion coefficient from either the concentration distribution or the sorption rate have been suggested for the laminate system.
Concentration distributions of p-aminoazobenzene (PAAB) were measured by the use of repeated laminates and compared with those predicted by the theoretical treatment1). Film rolls composed of two different component films were used in the measurements. Over all diffusion coefficients Dov through the repeated laminates were calculated either from the observed concentration distributions in both component films or from that in one component film by employing the methods described previously1). Both agreed well with each other. With known Dov together with D through the partner component film, a method of calculation of diffusion coefficient D through a component film in a given repeated laminate was presented. In repeated laminates composed of nylon 6 with polypropyrene (Pp) or cellophane (Ce), values of D for PAAB through Pp and Ce were estimated using the method.