最新刊期
卷 ， 期 2 ， 1981
- 摘要：In this paper，we use the α-relaxation in dynamic mechanical behavior of poly (ethylene terephthalate (PET) as a probe，to detect the difference in the state of mole-eular aggregation of PET in the amorphous region under various conditions of draw-ing．Our studies show that，the quite different state of the amorphous regions of ori-ented PET samples can be obtained by variation of the speed and temperature of drawing，and the state of their amorphous regions is clearly demonstrated to be different by their a-peaks．Because the position，height and shape Df the a-peak in mechanical-10ss(Tan δ)-temperature curve reflect the intermolecular interactions and hence the state of the amorphous region of oriented PET sample，so that，those parameters show rea-sonable correlation with other mechanical behaviors and gome structure parameters of the PET sample．Furthermore，the experimental results show that there is an Arrhenius type equiva-lence between the draw speeds and the draw temperatures of samples with similar amorphous state．
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发布时间：2021-03-19 - 摘要：In this paper，the effects of procesmng and heat treatment of terephthalate／polyte-traoxymethylene block copolymer on their dynamic mechanical temperature spectra were studied．Combining with the stress-strain curve and other results，the relationships of the micro．phase seperation and mechanical properties have beea discussed．Our experimental results indicated that micro．phase separation mainly influnces the shape of Tg transition peak of the soft segments．The dynamic mecha-nieal temperature spectra of polyester/polyether block copolymers having three differ-ent chain structure measured with different temperature program were compared and the effect of chain structure on the erystallization of soft segments was discussed.Finally，the double glass transitions of polyurethane/polyether block copolymer were observed．Taking account of the effect of drawing on the double peaks and the differ-ence in their activation energy，we consider that the lower temperature peak is T1g of non-hydrogen bonded soft segment，while the higher temperature peak is T2g of hydrogen bedend soft segment．
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发布时间：2021-03-19 - 摘要：The spherulite growth behaviour of hard segment has been studied by SALS and other techniques for polyester-polyether block copolymers with low hard segment content. It has been found that the growth of spherulite is determined by the competition of two factors: the rate of phase separation of the components and the rate of crystal growth. The difference in crystalline morphology has slight influence on tensile property at low draw ratio but appreciably affects tensile behaviour, including tensile strength at high draw ratio.
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发布时间：2021-03-19 - 摘要：Silica of different structures and silica of the same structure but prepared by different surface treatments can be characterized by their apparent viscosity of dispersion in silicone oil, that was determined at a given shear rate and a given volume fraction.From the variation in dispersion visctsity before and after heat ageing in the confined condition it was found that the hydroxyl groups on the surface of silica are responsible for the degradation of polydimethylsiloxane chain. When the hydroxyl groups were replaced with methylsiloxy groups the thermal stability of the system was improved.
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发布时间：2021-03-19 - 摘要：In order to elucidate the relationship between the structure of the dinitriles and the polymerization rate and the oxidative thermal stability, the dinitriles with benzoxa-zole, benzoxazinone and phthalimide rings were synthesized by the following routes:polymerization rate of the dinitrile II with benzoxazole ring and IV with phthalimide ring was similar to that of the dinitrile I with benzothiazole ring at 300℃ and using 1.0％ of zinc chloride as the catalyst．The infra-red spectrum of the polymers from II and IV showed a S-triazine structure with the characteristic absorptions at 1506, 1354，811cm-1 and 1510，1350，cm-1．respectively，and the disappearance of the nitrile absorption at ca．2230 cm-1．But the dinitrile III with benzoxazinone ring polymerized much slowly at the same conditions．The isothermal weight loss at 371℃ in air during 200 hours of the polymers from these dinitriles was measured and compared with that of the dinitrile I．The results indicated that the oxidative thermal stability of the polymers from the dinitriles II．IV was inferior to that Df the dinitrile I．
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发布时间：2021-03-19 - 摘要：In order to determine the influence of the different position of the cyano group in the dinitrile with benzothiazole ring upon the polymerization rate and the oxidative thermal stability of the polymers and to ascertain the excellent oxidative thermal stability of the polymers from the dinitrles with the benzothiazole ring, the dinitriles Ⅰ-Ⅲ with 5-cyano-benthiazole ring were synthesized by the following routes: The polymerization of these dinitriles was investigated．The polymerization rate of the dinitriles I and II was similar to that of their 6-eyano analogues IX and X．The infra-red spectrum of the polymers from I—III showed a s-triazine structure with the characteristic absorption at the region of 1510．1360 and 820 cm-1 and the disappearance of the nitrile absorption at ca．2230 cm-1．The isothermal weight loss at 371° in air during 200 hours of the polymers from these dinitriles was measured and compared with that of the polymers from dinitriles IX and X．The results indicated that the weight losses were all low and similar of that of the polymers from IX and X．From the above results，we can conclude that the different position of the eyano group，whether at 5-or 6-position，has no influence upon the polymerization rate and the polymers from all these dinitriles with 5-or 6-cyano[Ienzothiazole ring possess excellent oxi-dative thermal stability．
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发布时间：2021-03-19 - 摘要：Two simple methods for correcting instrumental spreading in gel chromatcgraphy are suggested on the basis of the result of the moment analysis of Tung's integral equation. A correction factor ξ is introduced for correcting the experimental chromatogram. In the case of linear gel chromatograpbic column, identical results will be obtained by the way of correcting the calibration curve. It is shown that the instrumental spreading function can be defined as G(V, VR) = lim F(V), in which BM* represents the slope of the real relationship between thelogarithm of molecular weightand elution volume of a polydisperse sample.
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发布时间：2021-03-19 - 摘要：Zerovalent π-bis (benzene) chromium (O) is able to catalyze the polymerization of perfluorobut-2-yne to form polyperfluorobut-2-yne, a white powder, which is insoluble in common solvents and stable towards concentrated nitric acid, sulfuric acid and alkali. TG, DTA and DSC analysis show the polymer is surprisingly stable in air. Oxidative degradation does not occur until 470℃ in air. The activation energy for thermal degradation in air is found to be 56.5 kcal/mole. When the polymerization is carried out in toluene solution,benzens is detected by GLC.A possible mechanism is proposed.
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发布时间：2021-03-19 - 摘要：The effect of some impurities contained in butadiene produced by the oxidation-dehydrogenation of butene was studied in its polymerization with rare-earth catalytic system. In all cases, the catalytic activity decreased as the amount of the impurity was increased and the effect was in varying degrees with individual impurities. The molecular weight of the polymers obtained increased with decrease in catalytic activity.
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发布时间：2021-03-19 - 摘要：Anionie monofunctional polymerization and difunctional Polymerization of HFPO with perfluorinated acyl fluoride in presence of potassium fluoride have been studied．We found that under ordinary pressure the activity of monofunctional polymerization of HFPO in presence of potassium fluoride is much smaller than that in pre-sence of cesium fluoride reported in the literature，and in the presence of potassium flnoride the activity of difunctional polymerization of HFPO is larger than that of mono-functional polymerization．We also found that the emulsified layer formed at the end of the polymerization shows catalytic activity．it may has the composition of K+- OCF2RfCF2-O-K+．It catalyses the monofunetional polymerization of HFPO during the difunctional polymerization．A mechanism is suggested to explain this catalytic phenomenon．
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发布时间：2021-03-19 - 摘要：This paper is an attempt to describe the role of the radiation of the far．infrared ray in oxidation of the PAN fiber by heating in air．Oxidation．effect of the PAN fiber by heating in air under radiation of the far-infrared ray has been investigated by infrared spectroscopy，DSC，DTA，elemental analysis，X-ray and electron microscopy techniques．The analytical results indicate that radiation of the Farinfrared ray ef-fectively promotes oxidizing·cyelizing reaetions of the PAN fiber by heating in air．The most important characterisitics of the oxidized fiber (by heating in air with radiation of the far-infrared ray) appear to be the presence of more oxygen and the formation of oxidized-cyelized more thick sheath．During oxidation，unsaturation，hydroxyl and carbonyl groups are introduced，and thermally stable ladder polymer is formed．
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发布时间：2021-03-19 - 摘要：The interface interaction between epoxy adhesive (E-51) modified with earboxyl-terminated liquied butadiene-acrylonitrile rubber (CTBN) and aluminum surface has been studied by reflection-absorption infrared spectroscopy．Our spectroscopic results indicated that significant difference in the shear strength of adhesive-aluminum joints formed by using imidazole (EWI2,4) and m-phenylene diamine as curing agents can be at-tributed to their differences，in the interfacial structure．As it was shown from the reflection-absorption spectra，the aluminum film peeled from the latter adhesive joint，i.e. one cured with m-phenylene diamine．is tom prised of CTBN as the main component at the interface.
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发布时间：2021-03-19 - 摘要：A new route to polyamides -was established on the polycondensation of a new typical active diester, active diester of N-hydroxy-5-norbornene-2,3-dicarboximide such as N,N'-(isophthaloyldioxy) bis(5-norbornene-2,3-dicarboximide) and N,N'-(terephthaloyl-dioxy) bis (5-norbornene-2,3-dicarboximide) with diamines including ethylenediamine and hexamethylenediamine. The polycondensation occurred at room temperature without added catalyst in solution.
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发布时间：2021-03-19
Research Article
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