Mg(OH)2/Al(OH)3/包覆红磷阻燃SEBS/PS共混物

研究了Al(OH)3,Mg(OH)2包覆红磷(10份)对苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)/聚苯乙烯(PS)阻燃性能的影响.结果表明,Mg(OH)2用量为80份时阻燃级别达V-2,氧指数达到29%,但力学性能较差;AI(OH)3用量为80份时阻燃效果不很理想,但对力学性能影响较小;Mg(OH)2/Al(OH)3/包覆红磷体系中Mg(OH)2用量大于Al(OH)3时综合阻燃效果最好.阻燃体系的热释放速率降低,有效燃烧热出现峰值延后.     

Mg(OH)2及其与红磷复配阻燃聚丙烯复合材料的性能研究

研究了Mg(OH)2和Mg(OH)2/红磷复配体系阻燃聚丙烯材料的性能,选用热塑性弹性体POE对阻燃聚丙烯复合材料进行了增韧改性,结果表明:Mg(OH)2与红磷复配可以减少Mg(OH)2用量,降低对材料力学性能的损耗;POE较好地改善了材料的冲击性能,其添加量为15份时,材料的冲击强度可由8.14kJ/m2增大至12.83kJ/m2。最后利用锥形量热仪验证了Mg(OH)2/红磷复配体系的协同阻燃效应。     

Mg(OH)2与包覆红磷协效阻燃PP/PA6复合材料的研究

研究了包覆红磷和Mg(OH)2/包覆红磷复配体系对聚丙烯/尼龙6(PP/PA6)合金性能的影响,分析了不同阻燃体系对PP/PA6合金的阻燃性能和力学性能的影响,选用热塑性弹性体POE-g-MAH对阻燃PP/PA6复合材料进行了增韧改性.结果表明:Mg(OH)2与包覆红磷能协效阻燃PP/PA6复合体系,当包覆红磷添加量为15份.Mg(OH)2为30份时,PP/PA6复合材料的氧指数从19.2%提高到27.5%;POE较好地改善了材料的冲击性能,其添加量为15份时,材料的冲击强度可由3.4 kJ/m2增大至8.6 kJ/m2,并保持良好的阻燃性能.     

无卤阻燃PC/ABS合金的研究

研究了四苯基间苯二酚基二磷酸酷(RDP)和氢氧化铝复配阻燃体系对PC/ABS合金性能的影响;并以马来酸酐接枝丙烯腈-苯乙烯-丁二烯共聚物(ABS-g-MAH)为相容剂,考察了ABS-g-MAH的用量对合金性能的影响.结果表明,复配阻燃体系可显著提高PC/ABS合金的阻燃性能,当RDP为14份、Al(OH)3为6份时,氧指数可达到32%;相容剂的加人能够明显提高合金的力学性能,最佳用量为6%,但使体系的黏度增加,熔体质量流动速率降低.     

Mg(OH)2、红磷协同阻燃PIB/LDPE体系的研究

研究了3种粒径的Mg(OH)2阻燃剂对聚异丁烯/低密度聚乙烯(PIB/LDPE)体系性能的影响。发现随着Mg(OH)2用量的增加,体系的极限氧指数(LOI)增加,拉伸强度和断裂伸长率下降;Mg(OH)2的粒径对体系的LOI影响不明显,但对力学性能的影响较明显,阻燃剂粒径越大,材料的力学性能下降越多。将Mg(OH)2与红磷复配用于PIB/LDPE体系,发现具有明显的阻燃增效作用。探讨了红磷、Mg(OH)2在此类聚烯烃体系中的阻燃增效机理。     

无卤阻燃剂在阻燃ABS制备中的应用

采用不同类型和不同用量的无卤阻燃剂与丙烯腈-丁二烯-苯乙烯共聚物（ABS）熔融挤出制得无卤阻燃ABS。考察了阻燃剂的种类和用量对ABS阻燃效果的影响。对研制的无卤阻燃ABS进行了氧指数的测试。结果表明：微胶囊红磷／Mg（OH）2组成的复合阻燃剂质量分数20．0％时，复合材料．ABS阻燃效果达到V-0级。     

PE-LLD／EVA／Mg（OH）2／复合阻燃剂高效无卤阻燃体系的研究

采用线形低密度聚乙烯/乙烯-醋酸乙烯共聚物作为复合材料主体,表面处理过的氢氧化镁(Mg(OH)2)为主阻燃剂,以微胶囊化红磷和自制硅类阻燃剂为核心的复合阻燃剂为阻燃增效剂,重点探讨了Mg(OH)2和复合阻燃剂的阻燃效果。结果表明,Mg(OH)2与复合阻燃剂并用具有良好的协同效应,当Mg(OH)2用量40份,复合阻燃剂5～7份时,可获得较高的氧指数,垂直燃烧试验通过FV0级,且材料抗静电能力提高,力学性能、加工性能较好。     

无卤阻燃剂在阻燃ABS制备中的应用

采用不同类型和不同用量的无卤阻燃剂与丙烯腈-丁二烯-苯乙烯共聚物（ABS）熔融挤出制得无卤阻燃ABS。考察了阻燃剂的种类和用量对ABS阻燃效果的影响。对研制的无卤阻燃ABS进行了氧指数的测试。结果表明：微胶囊红磷／Mg（OH）2组成的复合阻燃剂质量分数20．0％时，复合材料ABS阻燃效果达到V-0级。     

无卤阻燃聚丙烯性能研究

采用包覆红磷作为无卤阻燃剂对聚丙烯(PP)进行了阻燃改性.结果表明,将10份包覆红磷和80份的Mg(OH)2复配具有明确的协同阻燃效果,使体系氧指数达到29%且综合性能良好;利用锥形量热仪测定了PP/Mg(OH)2/包覆红磷体系的热释放速率、有效燃烧热和质量损失速率,从而进一步证实了该体系的阻燃效果.     

LLDPE/LDPE/Mg(OH)2/红磷高效阻燃体系的研究

采用线性低密度聚乙烯(LLDPE)、低密度聚乙烯(LDPE)作为阻燃体系的主体，用表面处理过的氢氧化镁(Mg(OH)2)作主阻燃剂，微胶囊化红磷作阻燃增效剂，重点探讨了Mg(OH)2和微胶囊化红磷的阻燃效果。结果表明：Mg(OH)2与红磷并用具有良好的协同效应，是LLDPE／LDPE的高效阻燃体系。     

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.     

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.     

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.     

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.