最新刊期
卷 ， 期 6 ， 1981
- 摘要：The thermal degradation of resde type phenol-formaldehyde resin was studied by thermal gravimetric analysis, differential thermal analysis, thermal mechanical analysis, thermal volumetric analysis and gas chromatography. The results indicated that the thermal stability of phenol-formaldehyde resin was related to the presence of dime-thylene ether linkage. The thermal stability decreased as the ether linkage increased. The mechanism of the thermal degradation of the resole type phenol-formaldehyde resin was related to the presence of dime-thylene ether linkage. The thermal stability decreased as the ether linkage increased. The mechanism of the thermal degradation of the resole type phenol-formaldehyde resin was discussed.
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发布时间：2021-03-19 - 摘要：The chemical change of four resole type phenol-formaldehyde resins in curing process was studied by infra-red spectroscopy. It was shown that the curing process of resoles, at first, proceeded by condensation reaction of methylol groups, and the formation of dimethylene ether linkage was predominant. During further curing process (150-200°) carbonyl group appeared. The formation of carbonyl group was not caused by the ixidation of methylene group, but was a result of splitting of dimethylene ether linkage. The mechanism of suring process of phenolic resole resins was discussed.
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发布时间：2021-03-19 - 摘要：In the present article, the changes of surface component induced by photodegradation in different environment have been examined by means of ESCA. It may be inferred from ESCA data, that the primary process in the photodegradation of PVC in atmosphere and at room temperature is the photooxdation, while in inert gas cleavage of C-Cl bond occurs accompanied with the elimination of HCl and the formation of polyene sequences of different lengths. Therefore, the photodegradation of PVC is dependent on the environment to which PVC is exposed.
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发布时间：2021-03-19 - 摘要：The rib fractography of cross-linked PMMA has been explored by optical microscopy. It was observed that there was a direct connection between the fractographs, the fracture path and the crack tip crazes or microcracks in rib region. The rib consisted of one sandmark and one rough shattered belts. The former corresponded to peeling at the wedge craze/solid polymer interface, the later to shearing of microcrack shower which was formed ahead of sharpened crack tip. These two processes may be explained by "slip-stick" model. It was observed on unstable rib that the crack pro-pagation mechanisms in both mist and rib regions may transfer into each other.
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发布时间：2021-03-19 - 摘要：The accelerating effect of oxygen in the benzophenone／triethylamine／oxygen (BP/TEA／O2) system was studied．It is necessary to keep high concentration ratio of TEA／O2 in order to achieve the accelerating eftect．Experimental results indicated that oxygen in the system through photooxygenation reaction transformed to peroxides．The rate of oxygenation depended on[BP] and [TEA]0.8 Subsequent photosensitized de-eomposotion of peroxides led to an increase in forming primary radioals．Ftom the determintd Kp／Kt1/2 value it may be interpreted as the evidence of the primary radical termination．The kinetic orders related to Dhotooxidation of oxygen have been deter-mined and the corresponding reaction mechanisms are also discussed．
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发布时间：2021-03-19 - 摘要：The fine structure of PPTA mat-like crystal has been studied by solvent etching technique and electron microscopy．It has been found that the mat-like crystal is made of zigzag fibrillar structure oriented along the shear direction in the film．The periodical length of the zigzag fibrils is about one micron，corresponding to the width of a band in mat-like crystal．Therefore．the morphology of mat-like crystal observed by polarizing microscopy is an optical effect resulted from the periodical structure of the zigzag fibrils．The structure of an isolated fibril has also been observed． It is made of consecutively linked plates which may be formed from the moleeular slipping within the domain structure during the shear process．A new model is suggested to explain the structure of the PPTA film with mat-like crystalline morphology．
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发布时间：2021-03-19 - 摘要：The yield of copolymerization of tetrahydrofuran and propylene oxide (THF：PO =5--15，by wt.) using a binary catalyst of fuming sulfuric acid (21％ or 28％) and perchlorie acid is around 50一—60％，and the loss of THF in the reaction is below 10一15％． The average molecular weight of the product can be controlled in the range of 1000--2000 by varying the binary catalyst system．In difference with the usual product of copolymerization initiated by BF3一diol or SbCl5-diol system，the yield of copolymerization with the low PO feed is not decreased，the hydroxyl functionality is equal to 2，the end-groups are predominantly primary hydroxyls (around 65--70％) and the product is colorless．
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发布时间：2021-03-19 - 摘要：The oxidation and polymerization for the system of triethylenedimethaerylate (TEGMA)-dimethyltoluidine (DMT)，triethylenediaerylate(TEGA)．DMT，2-hydroxypro-pylmethaerylate (HPMA)-DMT in the presence or absence of oxalic acid have been studied．The results show that oxalic acid posseses much high antioxidizing and inhibi-ting power than hydroquinone，therefore，it is an effective antioxidant and inhibitor for the system of acrylic ester-amine．The chief function of oxalic acid would be antioxidation．since the oxidation of the system of acrylic ester-amine in the presence of small amount of oxalic acid will nearly stop，therefore the accumulation of the peroxide be comes very difficult．This may be the reason for the stability of this system as we]l as the others such as polypro-pylene and polyamides etc．in the presence of small amount of oxalic acid．
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发布时间：2021-03-19 - 摘要：A butadiene．styrene copolymer of low styrene content (5％，Wt．)has been eharac-terized by 1H NMR to have only isolated styrene units on the chain．The fluorescence spectra of the sample in dilute solutions of a good solvent (dichloroethane) at 25-—26℃ showed monomer fluorescence only．ChangeS of the fluorescence spectra from a good sollvent to poor solvents (dichloroethane-methanol mixture)．and from dilute to con-centrated solutions up to the solid film confirmed that exeimer formation exists between nonadjacent ehromophores in the chain and between interchain ehromophores． Com-parision of the spectra obtained from a dilute θ-solution and solid film gave us an estimation of the relative importance of the intrachain excimer interaction and inter-chain exeimer interaction in the solid sample studied．These results may help us to visualize the interpenetration and entanglement of polymer coils during transition from a dilute solution to a concentrated one and to a solid polymer．
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发布时间：2021-03-19 - 摘要：The influence of a polycondensation additive, triphenyl phosphate, on, the overall crystallization rate of PET has been studied by means of depolarized light intensity method and differential scanning calorimetry. The crystallization rate of PET in the low temperature region near Tg does not decrease, when TPP is added into PET by mixing in the melt state. The characteristics of the effect of TPP on the crystallization of PET indicate that TPP is a plasticizer of PET, but not a nucleating agent. The crystallixation rate of PET samples added with TPP could be predicted from that of the pure PET accouding to their depression in Tg and Tm.
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发布时间：2021-03-19 - 摘要：2-Hydroxy-3-dialkylaminopropyl methacrylate has been synthesized from glyeidyl methaerylate with dialkylamine．and then polymerized in bulk with various radical in-itiators．It was found that they did not polymerize with BPO，but could polymerize normally with other peroxides or hydroperoxides，such as CHP，LPO，TBH and KPS．The polymerization of DEAHPMA with CHP, LPO and AIBN have been carried out respectively．From the overall activation energies of polymerization．we would suggest the redox nature of the initiation mechanism of the polymerization of DEAHPMA initiated with CHP or LPO．The suspension polymerization of DMAHPMA has been carried out easily and successfully in 10％ NaCl aqueous solution without any addition of suspension stabilizers．
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发布时间：2021-03-19 - 摘要：Three sets of PET samples，comprising original (undrawn)，uniaxially drawn and biaxially ones，after annealed at 230°，240°and 250℃ respectively，were subjected to D8C t11ermal analysis．X-ray diffraction analysis and IR analysis．The results indicate that the phenomenon of double melting peaks during DSC analysis is due to the partial melting and recrystallization of the erystallite at the moment of thermal scanning．The lower temperature peak，which varies slightly according to annealing condition，cor-responds to the melting of imperfect crystallite，and the higher temperature peak corresponds to the melting of better organized crystallite．In the course of temperature scanning，the unit cell parameters of PET remains unchanged while the crystals turn to better crystal lattice。greater crystal size and more regular folding．We also found that there is a slight reduction in crystal size between the two melting peaks，and an explanation is suggested for this phenomenon．
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发布时间：2021-03-19 - 摘要：Polymerization of methylphenylphosphinic acid with zinc oxide has been investigated in aqueous media. Two species of polymer were obtained at the same time. One is crystalline, the other membranous (amorphous).They are allotropes. Using Onsager's equation, it has been shown that the soluble part of the polymer are in the form of ionic Zn++, MePhPO2- in aqueous solution, and so hydrolysis of this kind of polymers seems to be the process of dissolution and recrystallization in aqua.
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发布时间：2021-03-19
Research Article
- 摘要：The authours have shown in previous paper that the monomers, the molecules of which possess intermolecular hydrogen bond，polymerize in bulk．In the present study the N-ethylacetatomethylaerylamide is polymerized in solution of acetone and benzene．Examination of the infrared spectra of the N-ethylacetatomethylacrylamide ahows that the compounds possess intermolecular hydrogen bond in the condensed sate．It has been found that polymerization rate is the fastest in acetone，it is faster in benzene and is slow in bulk． It has been also found that in the same solution the more dilute the concentration．the more fast the polymerization rate．The change in polymerization rate of N-ethylacetatomethlaerylamide confirms the dependence of the polymerization rate upon the possibiSty of the formation of inter-molecular hydrogen bond．
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发布时间：2021-03-19 - 摘要：The degree of imidization of amine salt was determined by thermal analysis. It appears that imidization process occurs before the ending of amidation.
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发布时间：2021-03-19
Research Bulletin
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