ACS用量对CPVC-ACS复合材料的性能影响

采用机械共混法制备了氯化聚氯乙烯(CPVC)、丙烯腈-氯化聚乙烯-苯乙烯(ACS)二元共混复合材料(CPVC-ACS),研究了共混复合材料的组成与材料力学性能、耐热性能、阻燃性能和抗老化性能的关系。结果表明,ACS加入到CPVC中,可达到良好的增韧效果,但ACS用量的增加使CPVC的拉伸强度和维卡软化点温度降低;ACS对CPVC的阻燃性能影响不大,改性CPVC均可达到难燃级;用ACS改性CPVC的抗老化性能明显优于CPVC-ABS。     

PVC/ACS/CPE三元共混体系性能研究

采用机械共混制备了聚氯乙烯(PVC)/丙烯腈-氯化聚乙烯-苯乙烯共聚物(ACS)/氯化聚乙烯(CPE)三元共混合金,研究了共混体系的组成与合金力学性能及耐热性能的关系。结果表明,不同型号PVC对合金的性能影响不同,随着PVC摩尔质量的增加,共混合金的拉伸强度、冲击强度、热变形温度、硬度及氧指数逐渐增大,熔体质量流动速率(MFR)下降;随着共混合金中CPE用量的增加,PVC/ACS/CPE共混合金的冲击强度上升,氧指数增大,拉伸强度、弯曲强度、弯曲模量、热变形温度及MFR下降。     

CPVC/ABS/AS与CPVC/ABS共混体系性能研究

研究了丙烯腈丁二烯苯乙烯共聚物(ABS)含量对氯化聚氯乙烯(CPVC)/ABS/丙烯腈苯乙烯共聚物（AS）及CPVC/ABS共混体系力学性能、耐热性能以及阻燃性能的影响。结果表明,在CPVC/ABS/AS三元共混体系中,当ABS含量由零增加到30 %（质量分数,下同）时,共混体系的冲击强度由11.5 kJ/m2上升至39.1 kJ/m2;在CPVC/ABS二元共混体系中,当ABS含量由零增加到25 %时,共混体系的冲击强度由11.1 kJ/m2上升至52.6 kJ/m2,拉伸强度、弯曲强度和维卡软化点随着ABS含量的增加而下降;共混体系的阻燃性能与CPVC用量密切相关,在CPVC∶ABS（或ABS+AS）=6∶4时,共混体系的极限氧指数达到了31 %。     

CPE对CPVC管材的改性

研究了CPE用量对CPVC体系力学性能、耐热性能和加工性能的影响。结果表明:①CPE与CPVC的相容性较好,可有效提高CPVC体系的韧性,但同时会降低其刚性和耐热性能;②CPE可降低CPVC体系的熔体黏度,延迟塑化,改善其加工性能;③采用CPE作为冲击改性剂,可生产出符合国家标准的CPVC管材,从而降低其配方成本。     

CPVC/ABS/CPE三元共混体系的组成与性能关系研究

研究了氯化聚氯乙烯(CPVC)、丙烯腈-丁二烯-苯乙烯共聚物(ABS)和氯化聚乙烯(CPE)三元共混体系的组成与性能之间的关系。结果表明,ABS树脂可以有效降低CPVC/ABS/CPE三元共混体系的平衡扭矩,缩短三元共混体系的塑化时间,改善其流动性;当CPE含量固定、共混体系中CPVC与ABS的质量比为7:3时,共混体系的拉伸强度和缺口冲击强度达到最佳,共混体系具有较好的综合力学性能;随着CPE含量的增加,三元共混体系的缺口冲击强度显著提高,CPE对三元共混体系具有优良的增韧作用,用量以15份为宜。     

PP/CPE共混性能研究

研究了氯化聚乙烯(CPE)用量对聚丙烯/氯化聚乙烯(PP/CPE)材料的熔融时间、扭矩、表观黏度、氧指数和拉伸强度的影响,并通过扫描电镜研究了共混物的拉伸断面结构。结果表明:熔体最大扭矩和熔融时间随着CPE用量的增加而下降,而平衡扭矩和表观黏度上升,当CPE质量分数介于33%～45%之间时达到最优配比。另外,随着CPE用量的增加,共混物的阻燃性能显著增加,但拉伸强度在CPE质量分数大于20%后稍有下降。     

PP/CPE/纳米Mg(OH)2复合材料的研究

研制了聚丙烯(PP)，氯化聚乙烯(CPE)，纳米Mg(OH)2复合材料，讨论了CPE和纳米Mg(OH)2对PP复合材料的机械性能和阻燃性能的影响。研究结果表明，随着CPE和纳米Mg(OH)2含量的增加，材料的抗冲击性能和阻燃性能得到改善。用该复合材料体系经挤出成型的管材，能够承受16MPa的环应力，无破裂，无渗漏。     

氯化顺丁橡胶与CR，NBR或CPE并用胶性能的研究

考察氯化顺丁橡胶(CBR)用量对其与CR，NBR或CPE并用胶的物理性能、耐老化性能和阻燃性能的影响。结果表明，随CBR用量的增大，CBR／CR和CBR／NBR的拉伸强度和拉断伸长率均下降，CBR／CPE的这两项性能均提高；老化或浸油后，3种并用胶的拉伸性能均随CBR用量的增大而下降；随CBR用量的增大，CBR／NBR的阻燃性能改善，CBR／CR和CBR／CPE的阻燃性能下降。     

新型ACS树脂综合性能的研究

本文主要研究了新型ACS树脂的流动性、力学性能、热性能、耐老化性能以及阻燃性能,并与ABS、AAS树脂进行了性能对比。结果表明：随着CPE含量的增加,ACS树脂的抗冲击性和阻燃性提高,熔体流动速率、拉伸强度、断裂强度和热变形温度都下降;并且ACS的抗冲击性能、耐候性和阻燃性远远高于ABS和AAS树脂。     

CPVC／PVC／CPE三元共混改性的应用

研究了CPVC/PVC/CPE三元共混物的物理力学性能和流变性能。结果表明 :共混物的维卡软化温度、拉伸屈服强度和熔体粘度随CPVC用量的增加而明显增加 ;CPE的用量为 4～ 8份时可明显改善共混物的冲击强度     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Wet Milling of Fe/Al/Al2O3 and Fe2O3/Al/Al2O3 Powder Mixtures

Wet milling of Al₂O₃-aluminide alloy (3A) precursor powders in acetone has been investigated by milling Fe/Al/Al₂O₃ and Fe₂O₃/Al/Al₂O₃ powder mixtures. The influence of the milling process on the physical and chemical properties of the milled powders has been studied. Particle refinement and homogenization were found not to play a dominant role, whereas plastic deformation of the metal particles leads to the formation of dislocations and a highly disarranged polycrystalline structure. Although no chemical reactions among the powder components in Fe₂O₃/Al/Al₂O₃ powder mixtures were observed, the formation of a nanocrystalline, ordered intermetallic FeAl phase in Fe/Al/Al₂O₃ powder mixtures caused by mechanical alloying was detected. Chemical reactions of Fe and Al particle surfaces with the atmosphere and the milling media lead to the formation of highly porous hydroxides on the particle surfaces. Hence the specific surface area of the powders increases, while the powder density decreases during milling. The fraction of Fe oxidized during milling was determined to be 0.13. The fraction of Al oxidized during milling strongly depends on the metal content of the powder mixture. It ranges between 0.4 and 0.8.     

Sintering of Si3N4-Y2O3-Al2O3

Sintering kinetics of the system Si₃N4-Y2O₃-Al₂O3 were determined from measurements of the linear shrinkage of pressed disks sintered isothermally at 1500° to 1700°C. Amorphous and crystalline Si₃N₄ were studied with additions of 4 to 17 wt% Y₂O₃ and 4 wt% A1₂O₃. Sintering occurs by a liquid-phase mechanism in which the kinetics exhibit the three stages predicted by Kingery's model. However, the rates during the second stage of the process are higher for all compositions than predicted by the model. X-ray data show the presence of several transient phases which, with sufficient heating, disappear leaving mixtures of β ' -Si₃N₄ and glass or β '-Si₃N₄, α '-Si₃N₄, and glass. The compositions and amounts of the residual glassy phases are estimated.     

Participation of lewis base on vinyl chloride polymerization with Al(C2H5)3CCl4 catalyst system

The polymerization of vinyl chloride has been investigated using an $\text{Al}\text{(}\text{C}{}_2\text{H}{}_5\text{)}{}_3\text{CCl}{}_4$ catalyst system in the presence of various Lewis bases. Effective Lewis bases are γ-butyrolactone, diglyme and diethylenetriamine which are multidentate. The rate of polymerization is dependent not only on the basicity of the Lewis base used but also on a coordination number of one. The latter is the predominant factor. For the effect of polymeric amines, a tentative hypothesis is discussed.     

Synthesis and Characterization of Ti0.33Ta0.33Nb0.33C and Ti0.33Ta0.33Nb0.33CxN1-x Whiskers

Ta_0.33Ti_0.33Nb_0.33C and Ta_0.33Ti_0.33Nb_0.33C _x N_{1− x} whiskers were synthesized via a carbothermal vapor-liquid-solid growth mechanism in the temperature range 900°-1450°C in Ar or N₂. The optimum temperature was 1250°C. Whiskers were obtained in a yield of 70-90 vol%. The whiskers were 0.5–1 µm in diameter and 10–30 µm in length. The starting materials that produced the highest whisker yield were: TiO₂, Ta₂O₅, Nb₂O₅, C, Ni, and NaCl. C was added to reduce the oxides, and Ni to catalyze whisker growth. NaCl was used as a source of Cl for vapor-phase transportation of Ta and Nb oxochlorides and Ti chlorides to the catalyst. The catalyst metal was recycled several times during the synthesis and was transported as NiCl₂( g ) according to thermodynamic calculations. The rate of formation and the chemical composition of the whiskers depended on the synthesis temperature, the choice of catalyst, and the atmosphere. At low temperatures, the whiskers were enriched in Nb and Ta, whereas the Ti content increased with increased synthesis temperature.