最新刊期
卷 ， 期 1 ， 1990
- 摘要：Inhibititing effects of charge-transfer complexes (CTC) of hindered amine，such as，di-isopropylamine (DIPA) and 2，2，6，6-tetramethyl-4-piperidinol (TMP) to react with oh-loranil (CA) or benzoquinone (BQ) on radic al polymerization of methyl methacryhte (MMA)，initiated by azobisisobntylonitrile (AIBN)，has been investingated by dirlatometric method．The results showed that these complexes demonstrated greater inhibiting efficiency than those of quinones and hindered amines to be used alone Especially CTC formation of DIPA with CA COluld inhibite more remarkable the tpolymerization of MMA in presence of AIBN．In addkion．polymerization to be process in solvents such as benzene and acetonitrile were compared with those of ku]k polymerization of MMA．TIhose tests all reveal that CTC are polymerization inhibitors so that the efficiency of inhibition will be determined through the feasibility of CTC formation in polymerizating system．In other words，the re sults prov-ed prdiminary inhibition by the mixture of quinones and hindered amine for MMA might be also to involes electron-transfer from tie hindered amine into huinones forming CTC of hindered amine cation and semiqulnones anion．The semiquinones anions are,the actual inhibiting species．
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发布时间：2021-03-19 - 摘要：Crosslinked polystyrenes containing subst tuted sulfonyl groups (RSO2 X:X = Cl, O(CH2)9 CH3, NH2, NHNH2, Na, CH2CH3 and OH; R =polystyryl) were prepared. The 1R spectra of these compounds were assigned and compared with that of polystyrene and small molecular analogues. The characteristic absorption bands of the> SO2 group bound to the polymers and the effect of the polymer backbone on the IR spectra were discussed.
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发布时间：2021-03-19 - 摘要：Chelating resins (PAS) bearing dithiocarbamate groups were prepared by the reaction of carbon disulfide with resin (PA) containing secondary amine, which were obtained from polyethylene polyamines and chloromethylthiirane. The adsorption ability and selectivity of PAS for metals were determined. The order of adsorption ability of PAS for metal ions is Au3+>Pt4+>Ag+>Hg2+>Cu2+>Pb2+>Zn2+.The maxmium adsorption capacities of PAS resin for Au3+ and Ag+ are much higher than that of PA resin. PAS resin exhibits excellent selectivities for moble metals.
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发布时间：2021-03-19 - 摘要：Melt crystallization kinetics of polypropylene (PP) in the blends of fire-retardant PP (FRPP) has been studied by JJY-1 Crystallization Rate Equipment. Conclusions about effect of fire-retardant additives on the crystallization behavior of PP in FRPP system have been drawn, fire-retardant additive APP and TBE can act as nucleating agents for PP crystallization, but when APP contents exceed 20%, it acts as a barrier to the PP crystallization growth.In the presence of fire-retardant additive PER, the PP chain-folded surface free en-ergy is increased,resulting in a decrease of PP crystallization nucleating and growth rete.However,fire-retardant additive TPP has no efficient effect onPP crystallization be-havior.
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发布时间：2021-03-19 - 摘要：The rheological properties of the mixed solution of cellulose/paraformaldehyde/dimethyl sulfoxied and polyacrylonitrile/dimethyl sulfoxied were studied by rotation viscometry and falling ball methods. The variation of apparent viscosity of the solution was discussed with shear, temperature and its composition. The rheological properties were closely connected with the micro-structures of the mixed solution
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发布时间：2021-03-19 - 摘要：Treating chloromethylated polystyrene with anthranilic acid and then various PdI2 complexes gave palladium complex catalysts. The colloidal palladium catalysts, containing rnetal particles of 2-13 nm in diameter, were prepared by the reduction of Pd2+-chelate resin complex with 1:1 methanol-water (pH = 12). The hydrcgenation activities of these catalysts were correlated with the polarity parameter, ET(25), of the solvents used in the reaction. The hydrogen uptaken increased with decreasing the electron donor constant, En, of the ligand of Pd complex. The colloidal Pd catalyst,containing meral particles of 4-5nm in diameter,was active ca-talyst for the hydrogenation of alkenes.
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发布时间：2021-03-19 - 摘要：In a capacitively coupled discharge witih external electrodes, vinyltrimethylsilane (VTMS) was polymerized. The polymer structure was characterized with IR, XPS, PGC/MS, X-ray, ESR and elemental analysis. A polymerization mechanism was speculated. The thermal property of the polymer was studied by means of TG analysis. The polymer is found to be amorphous through X-ray study. XPS examination indicates that oxygen is incorporated into the polymer chain when plasma gases are not added, and the C/Si ratios of poly-mer are lower than that of polymer in general. TG study indicates that the polymer has better thermal stability.
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发布时间：2021-03-19 - 摘要：Synthetic conditions and reaction mechanisms of polyvinylbenzylamine resin were studied by IR-Spectra. The result shows that polyvinylbenzylamine resin can be prepared by the method of various syntheses under the suitable conditions. Otherwise, secondary reaction will be occurred.
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发布时间：2021-03-19 - 摘要：The main chain liquid cryatal polymers with X-shaped mesogens and different flexible spacers were synthesized by solution polycondensations using the monomers 4, 4'-(alkylen-edioyldioxy) dibenzoyl dichloride and 2, 5-dihydroxyl-1, 4-phenylene di-p-ethoxybenzoate. The liquid-crystalline behaviour of the polymers was characterized by DSC, polyarizing microscope and X-ray diffractometre. It was found that at a temperature not much higher than the clearing point of the polymer melts the birefringence will reccur in a few minutes,This unu-sual behaviour of these polymers is explained as the result of molecular weight increase in the heating process.
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发布时间：2021-03-19 - 摘要：A scanning electron-microscope is used to study the affection of temperature, ultrasonic waves and different concentrations on the appeearance of xanthan gums. A transmissive electr-onmicroscope is used to study the appearance and molecular weight of the monomolecules of xanthan. A conclusion can be drawn that xanthan molecules have uniform secondary, tertiary and quantenary structures, and that the xanthan molecule is a right-handed double helix made up of 40 subunits. The relation between their primery and senior structures has also been stated. Its molecular weight is from 6,000,000to 25,000,000.
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发布时间：2021-03-19 - 摘要：The polymerization of methyl methacrylate (MMA) initiated with organic peroxide，such as benzoyl peroxide (BPO)，lauroyl peroxide (LPO)，and N，N—di(2-hydroxyalkyl)-p-toluid-ine，such as N，N—di(2-hydroxyethyl)-p-toluidine(DHET)，N，N-di(2-hydroxypropyl)一p-to-luidine(DHPT)，or tertiary aromatic amine such as N，N—dimethyl-P-toluidine(DMT)，N，N-dimethyl aniline (DMA) systems has been studied．The polymerization rate Rp, overall acti-vation energy of polymerization Ea，and the rate equation of MMA polymerization in toluene were determined respectively．It was found that the order of Rp as follows：BPO-DHET>BPO-DHPT>BPO—DMT>BPO—DMA>BPO，and the values of Ea for BPO-Amine systems were always smaller than that of BPO alone．In the MMA curing reaction using the BPO-Am-ine initiation systems can decrease the curing time and shorten the time required to reach the peak temperature．From the ESR studies on the free radical intermediates produced from the BPO-Amine-MNP (2-methyb2-nitrosopropane) systems，it reveals the formation of radicals 1—4(see Table 5)．The UV spectra of PMMA solutions reveal that the DHET and DHPT moieties are present as the end groups of polymer obtained by using BPO—DHET and BPO—DHPT initiation sy-stems．Based on these results．the initiation mechanism for BPO一DHET and BPO一DHPT initia—tion systems were proposed．
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发布时间：2021-03-19 - 摘要：GPC method was established for the determination of molecular weight distributions of poly-2, 6-dimethyl-1, 4-phenylene oxide. Toluene at roon temperature was used as the eluent instead of o-dichlorobenzene at 80℃ or toluene at 60℃ as reported in literature.From the data of GPC and of Impact strength of the modified PPO, there exists a relationship. Impact strength decreases as the low molecular weight content (M≤6000) increases.
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发布时间：2021-03-19 - 摘要：PBT films treated at various temperatures for different periods of time were studied by FTIR, WAXD, elementary analysis and the mechanical property measurement. The heattreat-ment promoted the ring-closing reaction to completion, and the molecular chain regularity, the length of the conjugated system in the polymer chain were improved. The mechanical properties and the thermal stability of the PBT films were obviously increased. The best condition for heat-treating was also given.
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发布时间：2021-03-19 - 摘要：Pentacosdiyne-8,10 acid-1 has been synthesized and deposited by LB techniques onto glass, quartz and gold-covered glass slides. X-ray diffraction has been used to investigate the periodic structure of the film and effect of polymerization on the structure. Seven Bragg peaks were observed in the 26 angle range of1°-15′. From this point, the spacings of the LB film and the angle of molecular orientation on the substrate were calculated. A model was employed to calculate the diffraction intensity which was in good agreement with the experimental pheno-menon of even-odd intensity oscillation.
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发布时间：2021-03-19 - 摘要：Photo-induced grafting polymerization of acrylamide (AAM) onto polyetherurethane (PEU) was studied with benzophenone (BP) as sensitizer under irradiation of 365 nm. The effects of irradiation time, concentrations of monomer and sensitizer on the grafting yield were investigated. The formatioin of graft copolymer was verified by its water absorption % and the scanning electron microscopy photographs. Some model compounds of PEU soft segment and hard segment were used to clarify the graft reaction mechanism, which was proposed to involve the hydrogen abstraction by excited triplet BP from a-carbon of the polyether segment and fr-om nitrogen of the hard segment. The produced redicals then initiate the graft polymeriza-tion.
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发布时间：2021-03-19 - 摘要：The copolymers of 1,4-butynediol (BD) and 4, 4'-diethynylbiphenyl (DEBP) in different ratios are first synthesized using (Ph3P)2PdCl2 as catalyst. The density, the swellability and the average molecular weights between crosslinks of all copolymers are measured. As the mole ratio of DEBP/BD is larger than 1/5, the best solvent of copolymers is benzene, but as that is 1/10, the beat solvent is ethyl alcohol, the. IR spectra of all copolymers are done, too.
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发布时间：2021-03-19
Research Article
- 摘要：The blood compatibility of material is strongly influenced by the surface properties of the polymer. In the present paper ESCA has been used to characterize the surface compqsltion and component distribution at different depth from air-sample interface of blended polyether polyester block copolymer. The result shows that there was a specific component distribution at the blended polyether polyester block copolymer sample with the specific ratio of PTMGT/PEGT = 60/40. The relationship among surface composition and surface structure with blood compatibility of polymer was discussed.
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发布时间：2021-03-19 - 摘要：A two-dimensional NMR study on high 1,2-polybutadiene is presented. The results confirm the 1H NMR assignment given in literatures, with a few different points.
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发布时间：2021-03-19 - 摘要：The macroreticular acrylonitrile-styrene-divinylbenzene copolymers (MR-PSA resins) have-been synthesized successfully by the suspension polymerization，using the linear polystyrene (PS)：linear pre-polystyrene (PPS) and mixture of PPS-cyclohexane as pore-creating agents．The morphological structure and porous structure of the MR-PSA resins have been studied by using scanning electron microscopy (SEM)，BET method and density-bottle method．From the micrography and porous-parameters of the MR-PSA resins．we found：When the crosslink-ing degree is same，the morphol9gical structure of the MR-PSA resins change from“gel—flake”into“gel-granule” with the increasing of the content of polymeric pore—creating agents ap-plied，and their porous structures are improved in the meantime．The morphological structure and porous structure of the MR—PSA resins are also dependent on the sort of polymeric pore—creating system，PPS—cyclohexane is the best in the three sorts of polymeric pore-creating sys-tem used．The copolymeric compositions and other properties of the MR—PSA resins have been studied by the FT-IR，TG-DTG and Kjeldahod’s method．
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发布时间：2021-03-19 - 摘要：One of the advantages for field-flow fractionation is that the sample fractions obtained from one or several runs can be concentrated and reinjected in-line. Procedure of this method is simple and the trouble caused by impurities contained in carrier solvent can be avoided. This technique can be used to study the band broadening effect caused by the system or to recycle a particular fraction of polymers/particles with broad molecular weight/particle size distribution. The approach for carrying out this concentration and reinjection procedure is shown in detail. Experiment for thermal field-flow fractionation is described by using polystyrene with molecular weight 20.6×106,but the principle is unversal for other kind of FFF subtechniques.
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发布时间：2021-03-19 - 摘要：A sequential photoinitiation. phenomenon was found in the benzophenone/triethylamine/ MMA radical photopolymerization system, which leads to increase of molecular weight, amine content of polymer formed with progressive irradiation time. The results, obtained demonstrate that the sequential photoinitiation originates from the photoreaction of active amine groups at the polymer chains with excited benzophenones producing a polymer radicals, which induce sequential polymerization. The effects of benzophenone and amine concentrations,oxygen co-ntent and chain requlator were studied. Reaction mechanism was also discussed.
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发布时间：2021-03-19
Research Bulletin
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