聚乙烯醇/淀粉/凤仙透骨草提取物复合膜制备及性能

以聚乙烯醇(Polyvinyl alcohol,PVA)、淀粉(Starch,ST)为原料,凤仙透骨草提取物(Impatiens balsamina extract,IBE)为抗菌剂,通过共混法制备抗菌复合膜,通过FTIR、XRD、SEM和热重分析对复合膜的形貌和结构进行表征及对力学、光学、阻隔、抑菌等性能测试分析。结果表明,IBE与PVA/ST基膜复合良好,制备的PVA/ST/IBE抗菌复合膜对大肠杆菌、白色葡萄球菌和枯草杆菌具有良好的抑菌作用,抑菌性能随着IBE含量的增加而逐渐提高；同时具有良好的力学强度,IBE添加量为12.5 mL的复合膜拉伸强度达到22.97±0.68 MPa,断裂伸长率相比PVA/ST基膜提升了79.22%；透明度有所下降,透光率下降了11.90%；氧气阻隔性能良好,氧气透过系数为1.771±0.196×10_-12 ^cm₃^.cm/(cm₂^.s.Pa),在环保包装、食品保鲜等领域具有广阔的应用前景。     

PA6/CaCl_2/E44复合体系的结构与性能研究

利用熔融挤出法制备了聚酰胺6(PA6)/CaCl2/环氧树脂(E44)复合材料,研究了E44用量对PA6/CaCl2/E44复合体系的结晶、力学、耐热、光学及加工性能的影响。结果表明:随着E44含量的增加,复合体系的熔融温度向低温方向移动,PA6结晶受到限制。复合体系的冲击强度、拉伸强度、弯曲强度、维卡软化温度均随E44含量的增加而表现为先增大后减小的趋势,当E44含量为3份时,复合体系的冲击强度、拉伸强度、维卡软化温度均达到极值,分别为8.9 kJ/m2、78.2 MPa、64.8℃,与PA6/CaCl2(6.0 kJ/m2、47.0 MPa、57.7℃)相比分别提高了48%、66%、12%。结合复合体系PA6/CaCl2/E44的光学性能得知,当E44含量为3份时,可以得到力学性能优良、维卡软化温度较高、透明性及加工性能较好的低熔点PA6/CaCl2/E44复合材料。     

丁腈橡胶/聚氯乙烯共混胶

探讨了丁腈橡胶(NBR)中的结合丙烯腈质量分数、NBR／聚氯乙烯(PVC)(质量比,下同)、增塑剂邻苯二甲酸二辛酯(DOP)用量、PVC聚合度对NBR／PVC共混胶性能的影响,研究了NBR／低聚合度PVC共混胶的力学性能及加工流动性能。结果表明,随着NBR中结合丙烯腈质量分数的增加,NBR／PVC共混胶的耐油性能明显增强,力学性能也相应有所改善;NBR／PVC为80／20～60／40时．NBR／PVC共混胶的综合性能较好;DOP用量对NBR／PVC共混胶性能的影响不大;聚合度为700的PVC更适合于生产NBR／PVC共混胶,其力学性能、加工流动性能、耐老化性能与德国Bayer公司生产的牌号为Perbunan NT／VC3470B的NBR／PVC共混胶相当。     

鱼鳞明胶/壳聚糖/薰衣草精油抗菌复合膜制备及性能

以鱼鳞明胶(SG)和壳聚糖(CS)为原料,薰衣草精油(LEO)为抗菌剂,通过共混法制备抗菌复合膜,通过FTIR、XRD、SEM和热重分析对复合膜的形貌和结构进行表征及对力学、光学、阻隔、抑菌等性能测试分析。结果表明,LEO与SG/CS基膜较好复合,与SG/CS基膜相比,当LEO添加量为1%时,复合膜具有良好的力学强度(26.36 MPa),断裂伸长率提升了12.96%；透明度有所下降,透光率为70.50%；耐水性能和水蒸气阻隔性能显著增强,含水率、水溶性和水蒸汽透过率分别下降了22.48%、30.49%和26.03%；DPPH自由基清除率提高了247.88%,抗氧化性显著提高；同时对大肠杆菌和金黄色葡萄球菌具有良好的抑菌作用。     

不同促进剂对PP/PP-g-MAH/脱硫胶粉共混物性能影响

选用促进剂N–环己基–2–苯并噻唑次磺酰胺(CZ)、四甲基秋兰姆(TMTD)和N–叔丁基–2–苯并噻唑次磺酰胺(NZ)作为脱硫再生剂,分别对废旧胶粉进行改性,制备脱硫再生胶粉,然后制备聚丙烯(PP)/马来酸酐接枝PP(PP-g-MAH)/脱硫胶粉共混物,研究共混物力学性能、流动性能、断面形貌、流变性能和热性能的影响。结果表明,添加促进剂TMTD的共混物力学性能和流动性能最好,拉伸强度为12.15 MPa,断裂伸长率为22.17%,缺口冲击强度为17.11 kJ/m²,熔体流动速率为2.867 g/(10 min);随着角频率增加,共混物的复数黏度减小,储能模量增大,当角频率相同时,添加促进剂TMTD的共混物的复数黏度最小,储能模量最大;添加促进剂后共混物两相间的相容性较好,提高了界面粘接力,以添加促进剂TMTD的效果最好。添加促进剂后共混物的熔点和结晶温度均增大,其中,添加促进剂TMTD的共混物的熔点最高,结晶温度最低。     

SIS/SBS/PP共混改性的研究

研究了新型聚丙烯(PP)合金材料的配方、制备、工艺及性能。分别讨论了不同用量的三元乙丙橡胶 (EPDM)、苯乙烯与异戊二烯嵌段共聚物(SIS)及苯乙烯与丁二烯嵌段共聚物(SBS)与PP组成的二元和三元共混体系对材料力学性能的影响。结果表明:SIS为PP较好的增韧剂,PP／SIS/SBS三元共混体系具有较好的协同效应,在某种程度上可以代替EPDM改性PP,共混改性后拉伸强度、扯断伸长率等性能优良。     

PVA/木醋液/PVA复合膜的制备和表征

制备了5种聚乙烯醇(PVA)/木醋液/PVA复合膜,并分别对其力学性能和透光率进行表征。研究结果表明PVA/贮藏桶上部白桦精制木醋液/PVA复合膜的平均厚度较小(0.67 mm);PVA/贮藏桶上部白桦精制木醋液/PVA复合膜的拉伸强度较大(82.47 Mpa);PVA/贮藏桶上部白桦精制木醋液/PVA复合膜的断裂伸长率较小(17.5%)。PVA/贮藏桶上部白桦精制木醋液/PVA复合膜的透光率较好。PVA/木醋液/PVA复合膜在木醋液抑菌膜领域具有开发价值。     

再生纤维素/壳聚糖/银纳米线抗菌复合膜制备及性能

以1-丁基-3甲基咪唑氯盐（[Bmim]Cl）为溶剂体系，通过微晶纤维素（MCC）溶解再生制备基膜，壳聚糖（CS）、银纳米线（AgNW）共混液包覆方法制备抗菌复合膜，通过FTIR、XRD、SEM和热重分析对复合膜的形貌和结构进行表征及对力学、光学、阻隔、抑菌等性能测试分析。结果表明，壳聚糖和银纳米线成功复合于纤维素基膜，与再生纤维素膜相比，当AgNW质量分数为0.5%时，复合膜的拉伸强度提升了12.2%，透光率保持在89.82%，氧气透过率下降了86.7%，且对大肠杆菌具有良好的抑制作用，制备出一种力学性能、光学性能、阻隔性能、抗菌性能优异的可降解纤维素/壳聚糖/银纳米线抗菌复合膜。     

石墨烯/聚合物复合材料的研究进展

介绍了石墨烯的制备与改性方法,概述了石墨烯/聚合物复合材料的制备工艺,主要有熔融共混法、原位聚合法、溶液混合法及乳液混合法,并总结了石墨烯对聚合物导电性能、导热性能、耐热性能、物理机械性能和气体阻隔性能的影响.     

SSS/AMPS/AA/MA四元聚合物合成及阻垢性能研究

磺酸基团对盐不敏感,具有较好的抗温抗盐能力,尤其是抗高价金属离子的能力。因此,磺酸盐类共聚物成为近几十年来人们研究的热点。以苯乙烯磺酸钠（SSS）、2-丙烯酰胺基-2-甲基丙基磺酸（AMPS）、丙烯酸（AA）、马来酸酐（MA）为单体,水作溶剂,过硫酸铵为引发剂,次亚磷酸钠为链转移剂,确定了最佳的合成条件,合成的SSS/AMPS/AA/MA四元共聚物对碳酸钙垢、硫酸钙垢、磷酸钙垢表现出较好的阻垢性能,同时具有良好的分散氧化铁的能力和较强的稳定锌离子的能力。     

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.     

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.     

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.     

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.