适用于3D打印技术的ABS/SEBS复合材料制备

采用热塑性弹性体苯乙烯–乙烯–丁烯–苯乙烯嵌段共聚物(SEBS)对丙烯腈–丁二烯–苯乙烯塑料(ABS)进行改性,制备3D打印ABS/SEBS复合材料,研究了SEBS的用量对3D打印ABS/SEBS复合材料流动性能、力学性能与热降解行为的影响。结果表明,随SEBS用量的增加,ABS/SEBS复合材料的熔体流动速率先增加后降低;随SEBS用量增加,ABS/SEBS复合材料的冲击强度增加,SEBS能提高ABS/SEBS复合材料的断裂伸长率,但同时也使拉伸强度和弯曲强度降低;随SEBS用量的增加,ABS/SEBS复合材料的热稳定性增加;当SEBS质量分数为15%时,ABS/SEBS复合材料在3D打印中的综合性能最好。     

SBS对3D打印ABS复合材料性能的影响

用苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)改性苯乙烯-丁二烯-丙烯腈共聚物(ABS),制备3D打印用ABS改性复合材料,研究了SBS的用量对ABS复合材料性能的影响。采用熔体流动速率仪表征了复合材料的熔体流动速率,万能力学试验机和悬壁梁冲击试验机测试了复合材料的力学性能。研究结果表明,随SBS用量增加,复合材料的熔体流动速率增加,5%SBS的加入能使复合材料的熔体流动速率增加42.1%;随SBS用量增加,复合材料的冲击强度增加,弯曲强度降低;SBS能提高复合材料的断裂伸长率,增加其韧性,但同时也使拉伸强度降低。     

增韧改性剂对ABS/DBDPE/Sb_2O_3共混体系性能的影响

研究了苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)、氯化聚乙烯(CPE)、ABS粉料、甲基丙烯酸甲酯-丁二烯-苯乙烯共聚物(MBS)和聚硅氧烷几种改性剂对ABS/DBDPE/Sb2O3体系的增韧作用。结果表明,SBS、CPE、ABS粉料、MBS和聚硅氧烷对阻燃ABS复合材料有很好的增韧作用,可获得具有良好阻燃性能和物理机械性能的复合材料,其中加入CPE、MBS及聚硅氧烷并不影响复合材料的阻燃性能。     

硅系阻燃剂阻燃PC及PC/ABS复合材料研究进展

综述硅系阻燃剂阻燃聚碳酸酯(PC)及PC/丙烯腈-丁二烯-苯乙烯塑料(ABS)复合材料的机理,以及无机硅、有机硅氧烷类、聚倍半硅氧烷及其衍生物、有机/无机杂化硅材料、带有双螺环磷酸酯和磷杂菲的硅系阻燃剂等在PC及PC/ABS复合材料中的应用进展。指出硅系阻燃剂是PC及PC/ABS复合材料用阻燃剂的发展趋势。     

氯化聚乙烯对ABS/PVC合金性能的影响

以氯化聚乙烯(CPE)为增韧剂,用双螺杆挤出机共混制备丙烯腈-丁二烯-苯乙烯塑料(ABS)/聚氯乙烯(PVC)合金。研究了PVC及CPE用量对ABS/PVC合金的拉伸强度、弯曲强度、缺口冲击强度、维卡软化温度、氧指数和熔体流动性的影响。结果表明,随着PVC用量的增加,ABS/PVC合金的拉伸强度略有增加,弯曲强度基本不变,冲击强度呈现先略增加然后显著降低的趋势,维卡软化温度降低,氧指数增加;随着CPE用量增加,ABS/PVC合金的缺口冲击强度增加,拉伸强度和弯曲强度降低,氧指数和维卡软化温度变化很小,当ABS/PVC/CPE为40/60/15时,合金的拉伸强度为39.8 MPa、弯曲强度为60.8 MPa、缺口冲击强度为18.3 kJ/m2,氧指数为29.7%。     

废纸浆/ABS复合材料的性能研究

研究了废纸浆、马来酸酐接枝苯乙烯-乙烯/丁烯-苯乙烯(SEBS-g-MAH)用量以及发泡对废纸浆/丙烯腈-丁二烯-苯乙烯(ABS)复合材料的力学性能和吸水率的影响;通过扫描电镜SEM分析了SEBS-g-MAH对未发泡和发泡废纸浆/ABS复合材料的增容效果.结果表明:废纸浆用量为30份和SEBS-g-MAH用量为20份时,未发泡和发泡复合材料的拉伸性能和缺口冲击强度都达到最佳;吸水率随纸浆用量的增加而增加,SEBS-g-MAH用量为20份时,未发泡和发泡材料吸水率都达到最低.发泡后的复合材料的拉伸强度降低,冲击性能和吸水率升高.SEBS-g-MAH能有效地改善ABS和纸浆的界面相容性.     

几种相容剂对PVC/ABS合金注塑料性能影响

研究了氯化聚乙烯(CPE)、乙烯醋酸乙烯酯共聚物(EVA)、甲基丙烯酸甲酯-丁二烯-苯乙烯共聚物(MBS)和丁腈橡胶(NBR)4种相容剂对聚氯乙烯/丙烯腈-丁二烯-苯乙烯共聚物(PVC/ABS)合金注塑料性能的影响。研究结果表明,4种相容剂均会降低PVC/ABS合金注塑料的弯曲性能和阻燃性;CPE和EVA综合性能较好,有利于注塑料的加工和使用;MBS和NBR对合金注塑料流动性的不利影响较大,不适用于PVC/ABS合金注塑料。     

ABS/Nano-ATH复合材料性能研究

采用熔融共混法制备出了丙烯腈-丁二烯-苯乙烯共聚物(ABS)/纳米氢氧化铝(nano-ATH)复合材料,研究了nano-ATH的用量对复合材料力学性能和阻燃性能的影响,并利用扫描电镜分析了nano-ATH在ABS基体中的分散情况。结果表明:随着nano-ATH用量的增加,ABS/nano-ATH复合材料的冲击强度和拉伸强度均是先升后降,分别在nano-ATH含量为10%和5%时达到最大值;nano-ATH的加入可以提高ABS复合材料的阻燃性能和弯曲模量,但随其用量的增加,nano-ATH在ABS基体中的分散性逐渐变差。     

SBS增韧回收ABS改性研究

利用聚甲基丙烯酸甲酯(PMMA)及丙烯腈-苯乙烯共聚物(AS)对丁二烯-苯乙烯-丁二烯(SBS)增韧的回收丙烯腈-丁二烯-苯乙烯塑料(ABS)进行改性以提高其表面硬度.研究结果表明,PMMA及AS在提高共混物表面硬度的同时还可以提高其拉伸强度、弯曲强度及硬度,而冲击强度则呈下降趋势;此外,添加PMMA的共混体系的各项力...     

ABS/AS复合材料的制备及其在乒乓球中的应用

制备了丙烯腈-丁二烯-苯乙烯树脂/苯乙烯-丙烯腈共聚物(ABS/AS)复合材料,研究了AS的用量对复合材料力学性能、耐热性、表面光泽度及耐磨性的影响。结果表明:随着AS用量的增加,复合材料的邵氏硬度D和冲击强度逐渐增大,维卡软化点逐渐升高,接近于AS的维卡软化点110oC;AS的加入改善了样品的表面光泽度,在AS用量为15%时达到最大值,继续添加AS,样品的表面光泽度下降。随着AS用量的增加,ABS/AS复合材料的耐磨性有所改善。SEM结果表明,AS可以与ABS形成较好的黏合作用,摩擦外力对于材料表面的形貌影响较小。     

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.     

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.     

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.     

Ag2O-Doped Bi2Sr2Ca1Cu2Ox Superconductors Prepared via Melt-Quenching

Ag₂O-doped superconducting Bi₂Sr₂Ca₁Cu₂O _x ceramics were prepared by a melt-quenching–reheating method. It is found that the Ag₂O-doped, as-cast specimens exhibit superconductivity ( T _c= around 80 K) by heat treatment at temperatures around 800°C even in an evacuated and sealed silica glass tube, while the undoped specimens do not and vaporize by the corresponding heat treatment. Conversion of the Ag₂O-doped, as-cast specimens into superconducting ceramics when heated in an evacuated vessel is explained in terms of the oxygen donor of Ag₂O in the specimen. This finding enables us to fabricate a desired shape of superconducting Bi₂Sr₂Ca₁Cu₂O _x ceramics sealed in metals or glasses. The addition of Ag₂O to Bi₂Sr₂Ca₁Cu₂O _x melt, however, had deleterious influences on the superconducting properties ( T _c and J _c) of the resultant ceramics when obtained by heat treatment in air.     

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.     

The System Si3N4-SiO2-Y2O3

Subsolidus phase relations were established in the system Si₃N₄-SiO₂-Y₂O₃. Four ternary compounds were confirmed, with compositions of Y₄Si₂O₇N₂, Y₂Si₃O₃N₄, YSiO₂N, and Y₁₀(SiO₄)₆N₂. The eutectic in the triangle Si₃N₄-Y₂Si₂O₇-Y₁₀(SiO₄)₆N₂ melts at 1500°C and that in the triangle Si₂N₂O-SiO₂-Y₂Si₂O₇ at 1550°C. The eutectic temperature of the Si₃N₄-Y₂Si₂O₇ join was ∼ 1520°C.