最新刊期
卷 ， 期 4 ， 1983
- 摘要：A kinetic study on the polymerization of butadiene with MoCl4OC8H17-(i-Bu)2AlO-as catalyst has been carried out. The factors influencing the polymerizationrate was researched. Some of kinetic parameters such as the efficiency of catalyst, the concentration of active center and its average life period, were determined.It was found that the polymerization rate is first order with respect to the concentration of both monomer and Mo catalyst. The apparent activation energy for the polymerization is 17.1 Kcal/mole,and the efficienyc of catolyst was found to be about 4%. The average life period of active center is a function of activation energy and poly-merization temperature,it can be expressed as ξ=eEa/RT Pn/Zp[Bd].
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：The influence of the melt temperature on the crystalline morphology of polytetra-fluoroethylene was studied by Small An．gle Light Scattering and Electron Microscope techniques． When PTFE was melt．crystallized from temperature below 400℃ under slow cooling rate,the rodlike morphology was obtained；when it Was crystallized from temperature above 455℃．the spherulitie marphology was formed．From the inteme-diate temperature range，the formed sheaflike morphology can be viewed under electron microscope：The DSC study shows that the change of morphology with melt tempera-ture is due to chain seission of macromolecules．The decrease of molecular weight of PTFE with heat-treat temperature was estimated by the measurement of heat of crystal-lization using Suwa’s relation and the deterioration of meehanieal property with the increase of heat-treat temperature was also notieed．
- 7
- |
- 9
- |
- 0
发布时间：2021-03-19 - 摘要：In this paper the dynamic mechanical preperties of POY spun at 1500-5000 m/min have been studied. Three peaks of a loss tangent have been shown: α1, α2 and the superposition of α1, α2. It reflects that as the spinning speed increases the amorphous regions of POY change from liberal to double and finally to a network.In order to correlate the molecular motion, the fibre formation and structure with the mechanical properties of POY, we introduce a molecular motion parameter which can be defined as. Experimental results show that there is a good relationship among ψ,structure parameter and mechanical properties.
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：We have verified the formation of exeiplex in the photopolymerization of AN ini-tiated with aromatic tertiary amines．From UV spectra and fluorescence spectra we are inclined to．believe that aromatic tertiary amine in the ground state will form charge-transfer complex (CTC) with AN which may be excited to exeiplex by irradiation (CTC excitation)，while in excited state it will also form exciplex with AN through local ex-citation．The order of photopolymerization rate of AN caused by loeal exciration is found to be CH3C6H4N(CH3)2>C6H5N(CH3)2>HOCH2C6H4N(CH3)2>CH3C6H4N(CH2CH2OH)2 and this is in agreement with the order of stern．Volmer constant for the quenching of fluorescence of amines by AN．The order of photopolymerization rate caused by CTC excitation is found to be CH3C6H4N(CH5)2>CH3C6H4N(CH2CH2OH)2>HOCH2C6H4N ·(CH3)2>C6H5N(CH3)2，which is in agreement with ability of donating electron of the substituted group on the benzene ring of aromatic amines．The presence of small amount of aromatic amine group a8 end-group in the polymer molecule has been deteeted by UV spectra．
- 35
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：Four new polymeric crown ethers (I，II，III，IV) were synthesized via direct cyeli-zation of poly-β-ehloroethyl glyeidyl ether with disodium polyethylene glycols[H-(-OCH2·CH2)m OH，m=1，2，3，4] The cation-complexing ability and catalytic activity of these polymeric crown ethers have also been investigated．These polymers，especially polymer (II) are effective phase transfer catalysts in WoIff-Kishner reaction，such as the for-mation of diphenylmethane from diphenylketone hydrazone，and in the halogen exchange reaction i.e．the transformation of bromooctane to iodooctane by KI．The activity of poly-mer (II) is comparable with that of dibenzo-18-crown-6 and 18-crown-6．These polymers can be easily recovered by simple filtration and reused． For Wolff．Kishner reaction the polymer (II) could be reused twice without remarkable loss of activity．But in the ease of the halogen exchange reaction, the recovered catalyst exhibited low activity．
- 37
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：Photopolymerization of MMA in micellar solution was studied kinetically using ben-zophenone／triethylamine system as initiator．Catalytic effects of miceUe in the polyme-rization with different type of surfactants，such as SDS，CTAB and Triton X-305，have been observed，in which ionic micelles are more elfectire ones．The polymerization rate and molecular weight of polymer increases with increasing coneentration of mieelle in solution．The solubilization aites of BP／TEA／MMA system in ionic mieelles have been established by UV and 1H nmr spectra．The results indicate that the reaetion takes place in the mieelle-water interface (Stern layer)．The orientation of the solubilized monomer molecules in the mieelles will result in an increase of the regularity of con- figurational sequence in the PMMA．
- 35
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：The morphology of graft copolymers and blends of cis-1, 4-polybutadiene and trans-1, 4-polybutadiene was studied by electron microscopy, electron diffraction and DSC. It is found that at room temperature trans-1, 4-polybutadiene lamellae disperse in amorphous cis-1, 4-polybutadiene matrix, while at low temperature in crystalline cis-1, 4-polybutadiene spherulites. This paper discussed the effect of trans-1, 4-polybudiene content on microphase separation: shperulite structure at low temperature and on tensile pro-perties of the copolymers.
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：An automatic capillary viscometer with photo fibers as the cold light source and a thermostate which maintains con stant within ±5×10-4℃ has been developed, giving an accuracy of ±4×10-3 sec. for determinating the time of flow in this capillary visco-meter. In this paper, the basic principle, construction, specifications and main features of this instrument were described.
- 33
- |
- 7
- |
- 0
发布时间：2021-03-19
Research Article
- 摘要：The degradation or hydrolysis of PET by sodium hydroxide was studied by infra red, dual ware length scanning thin layer chromatography, gel permeation chromatog-raphy and X-ray diffraction. It was observed that the concentration of sodium hydroxide may be greatly reduced by the addition of a certain amount of cationic surface active agent, quarternary ammonium salt.The alkali attacks and dissolves the PET from the surface of the fiber. At definife concentrotion of sodium hydroxide and dodeeyl dimethyl benzyl ammonium bromide the molecular weight or molecular weight distribution of the undissolved PET remains near-ly unchanged.
- 52
- |
- 14
- |
- 0
发布时间：2021-03-19 - 摘要：Dilithium initiator (LM-T) based on lithium-Aromatic complex was studied. Using LM-T as initiator and non-palar hydrocarbon as polymerization solvent, styrene-buta-diene-styrene triblock copolymer (SBS) was syntherized by one-step feed method. The characterization of SBS obtained by this initiator was curried out by means of IE, NME, GPC and mechanical properties determination. Comparison was made with sample prepared with monolithium initiator by twostep feed methed.
- 37
- |
- 9
- |
- 0
发布时间：2021-03-19 - 摘要：PET film annealed at different temperatures have been studied in the far infrared spectra region (300-400cm-1). A 6 cm-1 shift near 382cm-1 band was found between crystalline trans (Tc) and amorphous trans conformation (Ta). The 388 cm-1 band should be associated with Ta conformation.According to the normal vibrational analysis, the differences among Tc, Ta and amorphous structure correspoding to the departures from planarity of the PET molecular unit were discussed.
- 1
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：a-methyl styrene dimer was used as a regulator in the copolymerization of styrene and aerylonitrile. When a-methyl styrene dimer and the monomers were added dropwi-se into the system of emulsion copolymerization, very few monomer droplets were observed. Under this condition, the reaction was stable and a satisfactory method in controlling M. W. and the homogeniety of the copolymer composition was obtained.
- 0
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：Using allylamine as a chemical selective degradent, the morphological changes in drawing process of two PET samples with different crystallization rates have been investigated by means of scanning electron microscopy. Different types of morphology in different size of domain in the sample have been observed under different stretching conditions (including stretching mode, temperature, rate and stretching ratio).
- 2
- |
- 7
- |
- 0
发布时间：2021-03-19 - 摘要：Some new linear polysulphone-polydimethylsiloxane-ether urethane segmented copolymers were synthesized. The solution polyaddition reaction as well as the morphology and dynamic mechanical properties of the segmented copolymers were studied preliminarily.
- 32
- |
- 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