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【期刊论文】Modifications of ZSM-5 zeolites and their applications in catalytic degradation of LDPE
王玉忠, Qian Zhou, Yu-Zhong Wang*, Chao Tang, Yu-Hua Zhang
Polymer Degradation and Stability 80(2003)23-30,-0001,():
-1年11月30日
The combination of two modification techniques developed for the ZSM-5 zeolite, i.e., desilication and incorporation of lanthanum under microwave irradiation, has produced a highly efficient catalyst, DeLaZSM-5, for catalytic degradation of low-density polyethylene (LDPE). Its performance on the degradation was studied at 390C and compared with the parent ZSM-5 and the modified intermediate products desilicated ZSM-5 (DeZSM-5) and LaZSM-5. Among the catalysts tested, DeLaZSM-5 showed the highest catalytic degradation rate. In addition, on DeLaZSM-5 the liquid yield was slightly increased and the isoparaffin index of the liquid was almost doubled, which indicated higher liquid quality compared with the parent ZSM-5 zeolite. The high catalytic activity of DeLaZSM-5 could be explained by its unique acidic properties with a sharp increase of the number and strength of weak acid sites and a decrease of strong acidsites.
DeLaZSM-5 zeolite, Catalytic degradation, LDPE
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王玉忠, Li-Min Deng, Yu-Zhong Wang *, Ke-Ke Yang, Xiu-Li Wang, Qian Zhou, Song-Dong Ding
Acta Materialia 52(2004)5871-5878,-0001,():
-1年11月30日
To obtain a biodegradable polymer material with satisfactory thermal properties, higher elongation and modulus of elasticity, a new copolyester, poly(butylene succinate-co-ethylene succinate-co-ethylene terephthalate) (PBEST), was synthesized via direct polycondensation from three prepolymers of butylenes succinate, ethylene succinate and ethylene terephthalate (ET). The resulting copolyesters, PBEST, were characterized by 1H-NMR, DSC, TG and WAXRD, and their melting temperature (Tm), melting heat of fusion (DHm), glass-transition temperature (Tg), and thermal decomposition temperature (Td) (1.5wt%) were obtained. Compared to poly(butylene succinate-co-ethylene succinate) (PBES), PBEST has improved thermal properties such as higher Tm and Td due to the incorporation of poly (ethylene terephthalate) unit into the main chains of copolyesters, but very low crystallization speeds. The degradation test of copolyesters in a compost condition shows that the degradability of PBEST is as a function of content of ET.
Butylene succinate, Ethylene succinate, Ethylene terephthalate, Copolyester, Synthesis, Characterization, Biodegradability
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王玉忠, YU-ZHONG WANG
Journal of Polymer Science: Part B: Polymer Physics, Vol. 41, 2296-2301 (2003),-0001,():
-1年11月30日
The solubility behaviors of poly(sulfonyldiphenylene phenylphosphonate) (PSPPP), a very efficient flame retardant for poly(ethylene terephthalate) (PET), in more than 50 solvents were examined. Its solubility parameters (δ) were determined by the intrinsic viscosity and turbidic titration methods. The two methods obtained consistent results, δ=21.0-21.6J1/2/cm and δ=21.0J1/2/cm3/2, and the three-dimensional solubility parameters were δ=18.9J1/2/cm3/2, δ=8.8J1/2/cm3/2, and δh=5.9J1/2/cm3/2. The miscibility of PSPPP with PET was estimated by the calculation of the heats of mixing, which were related to the difference between the solubility parameters of PSPPP and PET. Fourier transform infrared was used to examine the interactions between PSPPP and PET macromolecules, which were the internal factors of polymer-polymer miscibility. The results showed that PSPPP and PET were miscible within a very wide composition range, especially with less than 15wt% PSPPP, a composition of interest for the preparation of flame-retardant PET.
poly (, sulfonyldiphenylene phenylphosphonate), , solubility parameter, miscibility, poly(, ethylene terephthalate), , flame retardance, intrinsic viscosity
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王玉忠, Yu-Zhong Wang, Bing Yi, Bo Wu, Bing Yang, Ya Liu
Journal of Applied Polymer Science, Vol. 89, 882-889 (2003),-0001,():
-1年11月30日
Potassium diphenyl sulfonate (SSK), poly-(sulfonyl phenylene phosphonate) (PSPPP), and their mixtures are proved to be effective flame-retardants for polycarbonates (PCs) by measuring the limited oxygen index values and UL-94 of blends. The flame-retardant systems are characterized by thermogravimetric analysis under dynamic conditions. The resulting data, together with the analysis of the activation energies, demonstrates that the additives ac-celerate thermodegradation, especially in the early stage, and different additives cause a different process in the final stage.
flame-retardant, polycarbonate, thermogravimetric analysis
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