最新刊期
卷 ， 期 5 ， 1981
- 摘要：Following a previous paper in which a successful synthesis of polyphenyl-as-tria-zine from 1，4-dicyanobenzene was reported，we have prepared five new polyphenyl-as-triazines from terephthalamidrazone and different aromatic tetraketones．These poly-mers were characterized by TGA，DTA，elemental analysis and 1R spectroscopy．nlnh were between 1.39—2.16dl／g(0.5％ cresol，at 25℃)．All properties were determined by using specimens in the fotin of films and wire coatings． Experimental results show-ed that these polymers exhibited good thermal-oxidative stability．hydrolytic stability and tensile strength at room temperature with the exception of polymer VI．The films of polymers (I)一(V) suffered 4.30一5.31％ weight loss after isothermal aging in air at 300℃ for 200 hours．There were no change in weight when these films were treated in water at 200℃ for 30 hours．Wire coated with polymer (I) at room temperature in water has a resistance of 1011---1012Ω．Wten it was boiled in 40％ NaOH solution as long as 24 hours or submerged in water at 200℃ for 100 hours，no change in insula-tion was deteeted．
- 4
- |
- 9
- |
- 0
发布时间：2021-03-19 - 摘要：The overall rate constants of propagation (kp) in the bulk polymerization of te-trahydrofuran using allyl bromide (AB) or sebacoyl chloride (SC) and silver perchlo-rate as binary catalyst systems were determined to be 0.32 × 10-3 and 0.38 ×10-3 l mol-1. sec.-1, resp. The evidently low kp values were interpreted by the high nucleophilicity of counterion ClO4-. With increasing the amount of AgClO4 in the composition of AB-AgClO4 catalyst system (up to 51% molar excess), the induction period of the initiation reaction decreases and the rate of polymerization increases,while the kp value would in-crease rather insignificantly.
- 4
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：The crystalline morphology of some FEP copolymers, prepared with different polymerization methods, with different hexafluoropropylene (F6) contents was studied by SALS technique.The results obtained show that the main factors which affect the crystalline morphology of the eopolymers are the content of F6, and the conditions for crystallization. The morphological structure of these copolymers could change from rod-like to spherulitical, as the F6 content changed from 2% to (14-19)% under usual air cooling condition.However,rod-like crystalline structure would form under very low rate of cooling (0.2℃/min). Some Hv patterns show that some fine structure also exists in addition to the two- and three-dimensional spherulites co-existiong in the specimens prepared under certain crystallization conditions.
- 4
- |
- 10
- |
- 0
发布时间：2021-03-19 - 摘要：The surface energy of some fluoropolymers such as copolymer of tetrafluoroethylene and hexafluoropropylene (F-46), polytetrafluoroethylene, fluororubber F-2311, F-2641 and fluoroplastic F-3M are determined from the measurement of the contact angle by the uses of Zisman's method, Fowkes' method and Yoshito's method.
- 36
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：The crystallization behavior of polyblends of PP with SBS block copolymer has been studied by means of polarizing microscopy, SALS, dynamic mechanical measurements and differential scanning calorimetry. Results show that the introduce of SBS could decrease the degree of crystallization of PP component in the polyblend and prevent its spherulite formation. These factors are all advantageous to the improvement of the impact resistance of PP plastics. It is also found from DSC measurements, that the overall crystallization rate of the polyblend during cooling from the melt is faster than that of the PP.
- 4
- |
- 8
- |
- 0
发布时间：2021-03-19 - 摘要：The dynamic spring analysis (DSA) has been improved by strengthening two ends of the spring. In this way the accuracy of measuring dynamic modulus was increased. The improved method can be applied not only to the rubbery state of polymers but also to their glassy state.The isothermal curing processes of the bisphenol A epoxy resin cured by 4, 4'-diaminodiphenylmethane were measured by the improved DSA method. The apparent kinetic analysis of the curing processes has been made.
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：The isotactic polypropylene glass was prepared by quenching the molten film in dry-ice ethanol solution(below--75℃)．The specific volume of the quenched film was 1.135 cm3／g at--25℃．The relaxation and crystallization process of isotactic polypropylene glass was fol-lowed by density measurement and IR spectroscopy．Below--40℃，the thermal expen-sion coefficient of amorphous isotactic-polypropylene Was found to be 2.4X10-4／℃ and increased to 4.0 x 10-4／℃ at--40 to--20℃．Over --20℃，volume contraction took place noticeably，indicating the presence of crystallization and relaxation of the frozen maolecules．Below--23℃，there Was no change of the absorbance ratio (A998cm-1／A974cm-1) of the IR spectra of isotactic·polypropylene glass．But when the quenched film was heated to above --20℃，this ratio and the crystallization rate increased gradually．Because of crystallization．the“true” Tg of amorphours isotactie polypropylene could not be determined experimentally by conventional methods．The“true” Tg is probably just above -20℃．
- 41
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：The supermolecular structures and erystallization behaviors of FEP copolymer were studied by small angle light scattering technique，microscopic observation and differen-tial scanning calorimetry respectively．The results obtained shows that the morphology of FEP copolymer is critically dependent upon the melt temperature．When the,melt held at temperature below 315—320℃ and began to cool at constant cooling rate．the scattering pattern obtained was circularly symmetric and can be assigned as randomly arranged lamellas morphology．When the melt held at temperature above 315—320℃．the scattering pattern for spherulites was obtained．With the increase of melt temprea-ture，the size of spherulites increases，which can be confirmed by optical microscope study，these results can be best interpreted in corelation with crystallization curves measured in the DSC runs which also have distinct changes at the tran ition temperature (315—320℃)．It appears that in the melt there exists some order regions．which act as nucleus of crystallization and may be destroyed at the transition temperature．The ef-fects of molecular weight and cooling rate on the types and sizes of morphology were also investigated．
- 37
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：The granular macro-reticular water-insoluble polyvinyl alcohol was prepared directly from PVA with terephthaldehyde as crosslinking agent and ethylene glycol or teteraethy-lene glycol as diluent via water in oil type suspension system. It has been acetylized or esterified to obtain tertiary amine group or carboxy group containing functional carriers. The carboxy group containing carriers would react further with N-hydroxysuccinimide to give the active ester which would conjugate effectively with protein or enzyme under mild condition.
- 3
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：Influence of the structures of some monomeric nitroepoxides [CH2 - CH- CH2 - R],R=H (Ⅰ), NO2 (Ⅱ), NO2 (Ⅲ), - OCH2CH2NO2 (Ⅳ), - OCH2CH2NO2 (V) on the reactivity in cationic polymerization and the properties of polymers has been studied. In the presence of boron trifluoride etherate-1, 4-butanediol as a catalyst system, the reactivity of polymerization of these monomers has been found in following sequence : (Ⅰ)>(Ⅳ)≥(Ⅴ)≥(Ⅲ)≥(Ⅱ). Some properties of the polymers and the copolymers with tetrahydrofuran, such as heat stability,chemical stability,glass transition tem-perature,tensile strength and elasticity of the crosslinking plymers have also been investigated.
- 3
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：Reactivity ratios for hydroxy．containing monomers such as 2-hydroxyethyl me-thacrylate (HEMA) and 3--methoxy．2-hydroxypropyl methacrylate (MHPMA) with acrylonitrile (AN) or acrylamide (AAM) systems have been determined for radical co-polymerization at 60℃ in different solvents．The reactivity ratios computed by Kelen-Tudos and the Fineman-Ross and intersection graphitic methods have been compared．The values of r1=0.22—0.25，r2=0.97—1.05 for AN (M1)．HEMA(M2)，in DMSO or DMF initiated either by azobisisobutyronitrile (AIBN) or by potassium persufate (KPS)-iso-propyl alcohol (IPA)，the reaction media and initiator would not play a pronounced ef-fect．While，in AAM-MHPMA or AAM-HEMA，the values of reactivity ratios are as follows：r1=0.0433，r2=3.98 for the former case。and r1=0.0535，r2=1.89 for the later case，respectively．These distinet different values between r1 and r2 showed that the AAM monomer is more difficultly enter to the eopolymer composition than the AN monomer．
- 40
- |
- 9
- |
- 0
发布时间：2021-03-19 - 摘要：Kinetic studies were carried out on the polymerization of MMA photo-initiated by benzophenone／triethylamine／oxygen(BP／TEA／O2) system．Experimental results shown that the rate of polymerization is directly proportional to [BP]0.25 [TEA]0.25 [MMA] [O2] and [IO]0.5. Some deviation from this relationship has been found in ease of too high concentrations of photosensitized initiation syrstem．This may be at- tributed to the strong enhancing cage deactivation and extinction of the intermediate products．The accelerating effect of oxygen in this system resulted an increase in the rate of polymerization to 1.4 times and a quantum yield to 4.4×102．
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19
Research Article
- 摘要：The viscosity of PP melt in very low shear rate region was measured by the falling ball viscometer at 230℃. It is shown that the falling ball viscosity can be regarded as its zero shear rate viscosity. A relationship between the zero shear rate viscosities of PP melt and its viscosity average molecular weights was found aslog η0 = 3.72 log Mη, - 15.569(230℃)
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：Alternating copolymer of cyclohexene and SO2 in the form of white solid has been synthesized successfully by using TBH as initiator in the presence of small amount of CH2OH and avoid the coloration of the product.Besides, we have verified that the small addition of CH2OH would also make the molecular weight of the polymer higher to one order of magnitute and its molecular weight distribution much narrower than that of the copolymer without adding CH3OH.This copolymer has been used as eletronic-beam resist material successfully.
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：A simple method was used to identify the alkylation of lanthanide in the catalytic system LnCl3-ROH-AlR3, based on the reaction MCl3+AlR3, → MRCl2, + AlR2Cl, a soluble chloride Cl-ion which coexists with alkylation of transition metal can be detected. It was also found that the catalyst system mentioned was thermal stable in the absence of solvent.
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：New momomers, β-hydroxy-r-(ortho-acetoxy)-benzoxy propyl methacrylate, β-hyd-roxy-r-(ortho-acetoxy)benzoxypropyl acrylate have been synthesized from aspirin with glycidyl methacrylate and glycidyl acrylate respectively, and then polymerized radically.
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19
Research Bulletin
- Postal code：100190
- Tel：010-62588927 Email：gfzxb@iccas.ac.cn
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备05002797号-8
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0