环氧化天然橡胶包覆CaCO3填充LDPE的技术

选用环氧化程度摩尔分数为25%的环氧化天然橡胶胶乳(ENRL-25)包覆轻质CaCO3,研究了处理方法、ENRL-25用量和CaCO3填充量对CaCO3 /LDPE(低密度聚乙烯)复合材料结构与性能的影响,并与钛酸酯偶联剂NDZ-201处理CaCO3进行了对比。结果表明:ENRL-25和NDZ-201湿法包覆CaCO3效果较好,使CaCO3 /LDPE材料在拉伸强度保持较高的情况下,拉伸弹性模量、撕裂强度和扯断伸长率得到有效的提高;在采用最佳改性剂用量时,ENRL-25改性CaCO3/LDPE复合材料的撕裂强度和扯断伸长率较优,而NDZ-201改性CaCO3/LDPE复合材料的拉伸强度和拉伸弹性模量较优。SEM的分析结果表明,包覆CaCO3与LDPE的界面作用强度提高,材料的破坏不是始于CaCO3粒子脱粘,而是始于基质的变形破坏。      

超细SiO2/NR复合材料的制备工艺及其力学性能

利用乳液共沉原理、正交实验法,研究了Na2SiO3·9H2O与盐酸在助剂的作用下生成的SiO2乳液与天然胶乳共凝制备超细SiO2/NR复合材料的工艺。结果表明:由Na2SiO3·9H2O的质量浓度、反应时间、反应温度3个因子适宜水平组合,采用乳液共沉法制备的超细SiO2/NR复合材料的300％定伸应力为6.43 MPa,拉伸强度为29.04 MPa,撕裂强度为56.88 kN/m,与纯胶、普通SiO2/NR复合材料相比,超细SiO2/NR复合材料的力学性能得到一定程度改善。在本实验条件下,超细SiO2/NR复合材料的最佳制备工艺条件(适宜的因子水平组合)是Na2SiO3·9H2O的质量浓度第1份为280 g/L、第2份为100 g/L,反应时间为30 min、反应温度为80℃。      

纳米晶纤维素补强天然橡胶的研究

采用共凝沉法制备了纳米晶纤维素/天然橡胶(NCC/NR)复合材料。对复合材料的微观结构、物理机械性能、动态力学性能、热稳定性分析结果表明，纳米晶纤维素在天然橡胶中分散均匀，对天然橡胶有较好的补强作用，复合材料的储能模量提高，损耗因子下降，但对天然橡胶的热稳定性影响不大。     

NR/ENR/SiO_2复合材料的阻尼性能研究

采用机械混炼的方法制备不同ENR含量的NR/ENR/SiO2复合材料,使用动态热机械分析仪(DMA)和橡胶加工分析仪(RPA)对NR/ENR/SiO2复合材料的动态力学性能和阻尼性能进行分析。结果表明:ENR对NR/ENR/SiO2复合材料的阻尼性能具有显著影响。动态热机械分析测试结果表明,随着ENR用量的增多,NR/ENR/SiO2复合材料在使用温度范围内的损耗因子积分面积增大,阻尼性能提高。橡胶加工分析频率扫描和应变扫描测试结果表明,在频率小于10 HZ不同应变时,加入了ENR的NR/ENR/SiO2复合材料的阻尼因子均高于NR/SiO2复合材料。扫描电镜分析结果证实,ENR的加入减少了SiO2的自聚,改善了填料在橡胶基体中的分散,从而使NR/ENR/SiO2复合材料力学性能得到提高。     

γ-纳米Al2O3补强耐磨橡胶衬板的性能研究

以γ型纳米Al2O3补强[天然橡胶（NR）/顺丁橡胶（BR）/炭黑]耐磨橡胶衬板,研究纳米Al2O3对橡胶衬板混炼胶的硫化特性和加工性能以及硫化胶的力学性能、耐磨耗性能和耐热分解性能的影响。结果表明,纳米Al2O3适宜的添加质量分数为3％,此时,橡胶衬板混炼胶的焦烧时间和正硫化时间延长、加工安全性改善但不会影响胶料的硫化程度,并具有较好的加工流动性;纳米Al2O3增强的橡胶衬板硫化胶具有更优异的综合力学性能,且其磨耗量降低了46.2％,初始降解温度提高了58 ℃以上,从而使橡胶衬板硫化胶具有良好的耐磨耗性能和热稳定性能。     

锌钼营养对苦瓜产量、品质及叶片氮素代谢的影响

采用田间试验、植株生理生化测定方法,研究了锌钼营养对苦瓜（品种株洲长白）产量、品质及叶片氮素代谢的影响。结果表明:在土壤缺锌、钼的条件下,叶面喷施一定范围质量浓度配比的硫酸锌和钼酸钠均可显著提高苦瓜产量,并可提高苦瓜蛋白质、可溶性糖、维生素C（Vc）和17种氨基酸,尤其是人体必需氨基酸含量,降低NO3-含量,改善苦瓜品质;锌钼营养还可提高叶片蛋白质、核酸含量以及硝酸还原酶（NR）活性,并降低游离氨基酸、NO3-含量和核糖核酸酶（RNase）活性。在对叶片氮素代谢的影响程度上,锌和钼的作用存在一定的差异,且锌和钼呈现相互促进作用。苦瓜产量与叶片NR活性,叶片蛋白质与硝酸还原酶活性、核酸含量呈极显著正相关,而苦瓜产量与叶片RNase活性、叶片蛋白质与游离氨基酸、叶片核酸与RNase活性、叶片NO3-含量与硝酸还原酶活性等两两相互间则呈极显著负相关。讨论了锌钼对苦瓜品质和氮代谢的影响机理。      

2种凝固工艺制备的天然橡胶热降解表观活化能

用热重-微商热重(TG -DTG )方法研究了在流动的空气状态下 2 种凝固工艺制备的天然橡胶(NR )的热降解动力学,用 O zaw a 方程求取不同转化率 α 时的反应活化能 E,外推至转化率 α 为 0 的表观活化能 Eα→0,并用 Coats-Redfern 方程求取不同的加热速率 β 的反应活化能 E,外推 β 为 0 的表观活化能 Eβ→0。结果表明:甲酸凝固制备的 NR 在空气气氛中热降解反应表观活化能 Eα→0 为 101.6 kJ/mol,Eβ→0 为 104.5 kJ/mol,确定其表观活化能为 101.6￣104.5 kJ/m ol;自然凝固 7 d 制备的 N R 热降解反应表观活化能 Eα→0 为 107.7kJ/mol,Eβ→0 为 106.6 kJ/mol,确定其表观活化能为 106.6￣107.7 kJ/mol。自然凝固工艺制备的 NR 热降解反应的表观活化能高于甲酸凝固工艺制备的 NR 热降解反应的表观活化能。      

基于湿法混炼的天然橡胶/白炭黑/炭黑复合材料的性能研究

采用湿法工艺制备了含50 phr白炭黑的天然橡胶(NR)/白炭黑母炼胶,为改善湿法母炼胶的定伸应力和耐磨性,添加炭黑作为第二相填料,研究炭黑用量和混炼工艺对复合材料性能的影响。结果表明：炭黑的加入顺序对NR/白炭黑/炭黑复合材料的性能具有重要影响。在热处理工序之后加入炭黑,能够增强填料-橡胶相互作用,提高复合材料的定伸应力和耐磨性;在热处理工序之前加入炭黑,能够发挥白炭黑/炭黑的协同效应,改善填料分散性,降低滚动阻力和提高抗湿滑性能。     

甘蔗伸长盛期乙烯利处理对节间ATP酶和转化酶活性的影响

研究了甘蔗伸长盛期100mg/L乙烯利处理对3个甘蔗品种桂糖11号、桂糖15号和新台糖16号的Ca2+-ATP酶、Mg2+-ATP酶、中性和酸性转化酶活性的影响。3个品种间Ca2+-ATPase与Mg2+-ATPase的活性有差异,但相同品种的Ca2+-ATPase和Mg2+-ATPase的活性变化趋势基本一致。在甘蔗伸长盛期100mg/L乙烯利处理可以提高节间1的Ca2+-ATPase和Mg2+-ATPase的活性。在甘蔗伸长盛期节间2的中性和酸性转化酶表现基本一致的动态变化趋势。100mg/L乙烯利处理可以提高节间2中性和酸性转化酶活性。结果表明,在甘蔗伸长盛期乙烯利处理促进甘蔗蔗糖代谢活动,提高能量代谢水平,从而促进甘蔗生长。      

杨梅硝酸还原酶活性与根瘤固氮活性的研究

离体根瘤的固氮活性的测定采用乙炔还原法,硝酸还原酶的测定采用改进活体法,测试杨梅各器官硝酸还原酶活性的差异和温度、化合态氮对硝酸还原酶活性和固氮活性的影响,研究结果表明:①确定1%的正丙醇为活体法测定杨梅硝酸还原酶时所使用的渗透剂的最佳浓度。②杨梅NO3- 还原的主要部位在叶片,根瘤的硝酸还原酶活性受到宿主植物和内生菌的影响。③温度对植物体内硝酸还原酶和根瘤固氮活性水平影响很大,温度太高抑制酶活性,20℃时杨梅各器官的硝酸还原酶活性均达最高点,根瘤的固氮活性也达最高点。④用含10mmol/LNO3-的Hogland营养液培养的植株各部位的硝酸还原酶活性均高于对照,10mmol/L的NH4+ 对植株的硝酸还原酶活性未见明显影响,但能抑制根瘤的固氮活性,其抑制程度高于NO3-。⑤硝酸还原酶活性和根瘤固氮活性之间没有直接关系。      

A Comparative Study of the Thermoplastic Polyurethane/Carbon Nanotube and Natural Rubber/Carbon Nanotube Composites According to Their Mechanical and Electrical Properties

The present study investigated Thermoplastic Polyurethane (TPU), Natural rubber (NR) and their composites in terms of their mechanical and electrical properties for developing wearable stretch sensors. Both TPU and NR were added 2 %wt Multi-wall Carbon Nanotube (MWCNT), then in order to test their influences on TPU/CNT and NR/CNT composites. The result showed that Young’s modulus and Yield point of this experiment were higher than bare TPU and NR, whereas their stress-strain hysteresis loops were bigger than bare TPU and NR. Moreover, the Gauge factor (GF) value of TPU/CNT was much higher than NR/CNT composites at 100 % strain with 7.08. TPU/CNT composites promise to have many applications in the field of stretch sensors with good stability and durability while NR and NR/CNT were easy deformed when the stretch was applied.     

In-plane shear properties of multistitched nano composites by bias tensile test

In this study, multistitched woven nano composites were developed and their in-plane shear properties were characterized. The in-plane shear strength of unstitched structure was low compared to that of the unstitched/nano structures. However, the in-plane shear strength of unstitched structure was high compared to the machine stitched structures because of stitching and stitching yarn-matrix interfacial region. Additionally, the in-plane shear strength of machine stitched/nano composite structure was slightly high compared to the unstitched structure. The multistitched and multistitched/nano structures had limited delamination in their cross-sections. Their delamination regions were confined at a narrow area due to multistitching. This was considered that the developed multistitched/nano composites has better demage tolerance compared to unstitched composites.     

真空辅助酸凝固天然橡胶加工性能的研究

天然橡胶（NR）的性能与制胶工艺密切相关,其中凝固是制胶工艺的重要环节。本文采用真空辅助酸凝固天然橡胶,对比自然凝固天然橡胶和酸凝固天然橡胶,探讨了真空辅助酸凝固对天然橡胶门尼粘度、理化性能、物理机械性能以及加工性能的影响。研究表明,不同凝固方法得到的NR理化性能有一定的差异,自然凝固NR的氮含量>真空辅助酸凝固NR的氮含量>酸凝固NR的氮含量,真空辅助酸凝固NR的塑性初值（P₀）和塑性保持率（PRI）比自然凝固和酸凝固NR的P₀和PRI都高,其中真空辅助酸凝固NR的PRI为85%,而酸凝固NR的PRI为75.7%。真空辅助酸凝固NR的交联密度高于自然凝固NR和酸凝固NR。真空辅助酸凝固NR的拉伸强度、拉断伸长率均高于自然凝固NR和酸凝固NR的拉伸强度、拉断伸长率,3种NR的拉伸强度分别为21.06、19.35、17.60 MPa。RPA测试表明,真空辅助酸凝固NR的弹性模量（G'）<自然凝固NR的G'<酸凝固NR的G',损耗因子（tanδ）变化趋势恰好相反,即真空辅助酸凝固得到的胶样的加工性能最好,自然凝固胶样次之,酸凝固胶样最差。     

Sound absorption properties of spiral vane electrospun PVA/nano particle nanofiber membrane and non-woven composite material

In this research, we fabricated a series of PVA membranes loaded with 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.% ZrC and 0 wt.%, 1 wt.%, 3 wt.%, 5 wt.% TiO₂ using a spiral vane electrospun machine respectively. There were 2 sizes of TiO₂ nano particles: 10 nm and 200 nm. We tested sound absorption properties of needle-punched nonwovens as well as the composite of nano membranes and needle-punched nonwovens by an impedance tube at the frequency range from 500 Hz to 6500 Hz. Besides, we tested morphological characterization of nano membranes by scanning electron microscope (SEM) and crystalline properties by X-ray diffraction (XRD). We investigated the sound absorption properties of composites as well as the effect of ZrC, TiO₂, nano particle sizes and cavity depth on sound absorption properties. Results showed that sound absorption properties of composites increased at the whole range of frequency compared to those of needle-punched nonwovens. When loaded with ZrC nano particles, sound absorption properties of composite shifted to a higher frequency region, and with increasing content of ZrC, sound absorption properties were better above 2500 Hz. However, when loaded with TiO₂, sound absorption properties were better at lower frequency. With 3 wt.% TiO₂, sound absorption coefficient reached the best at the frequency range from 500 Hz to 1500 Hz. Besides, 200 nm TiO₂ was more conductive to the increase of sound absorption properties at lower frequency region compared to 10 nm TiO₂. Sound absorption properties of composites with air back cavity shifted to a lower frequency region, too. SEM showed that there was nano particle aggregation when loaded TiO₂ nano particles. XRD showed that ZrC nano particles loaded in PVA nano fiber retained their crystalline structure while TiO₂ didn’t. It appeared from the results that nano particles had an effect on sound absorption materials, with different kinds and different sizes, sound absorption properties will improve in different ranges of frequency     

环氧胶／天然胶共混物中塑化剂的研究

在ＥＮＲ／ＮＲ共混物中，塑化剂ＴＢＥＰ、Ｄｉｏｌｐａｔｅ７０１７的平衡分配系数Ｋｄ随硫化程度的变化而变化，填充炭黑的共混物的Ｋｄ值减少，塑化剂起到降低ＥＮＲ相Ｔｇ和平衡两组份粘度的作用；ＮＲ／ＥＮＲ共混物能获得较优的减震性能和其他力学性能。     

Basalt nanoparticle reinforced hybrid woven composites: Mechanical and thermo-mechanical performance

Nanoparticles are gaining wider importance and increasing utility in many areas of engineering and technology. This investigative work is conducted to study the effect of incorporating basalt nano particles in composites with basalt/basalt and basalt/jute woven structures as reinforcement. The nanoparticles were developed from basalt, they were characterized and used for reinforcing composites of basalt and jute hybrid fabrics. The mechanical and thermo-mechanical properties of hybrid woven basalt reinforced epoxy composites were evaluated. Microscopic examination was carried out in order to analyze the internal structure and fractured surfaces. Interfacial characteristics, material morphology and failure was studied by use of Scanning Electron Microscope (SEM) and optical microscopy. Thermal stability was characterized by TGA. The results elaborated that the incorporation of basalt nanoparticles exhibited superior properties compared to the pure epoxy resin impregnated basalt fabric reinforced composites in terms of mechanical and thermal stability.     

Experimental off-axis tensile characterization of multistitched woven nano composites

The aim of this study was to understand the off-axis tensile properties of the developed two dimensional multistitched multilayer E-glass/polyester woven nano composites. It was found that the specific off-axis tensile strength of unstitched structure was higher than that of the machine stitched structure due to stitching caused filament breakages. But it was slightly lower than that of the machine stitched/nano structure. In addition, the specific off-axis tensile strength of machine stitched/nano composite structure was slightly higher than that of the machine stitched structure. When the nano silica material in the unstitched E-glass/polyester composite structure increased, the off-axis specific tensile strength and the modulus of the unstitched/nano structures increased whereas, the off-axis specific tensile strain of the unstitched/nano structures decreased. The damaged areas of the unstitched/nano structures increased, when the nano silica material in the unstitched E-glass/polyester woven composite structures increased. The failures under the off-axis tensile load of the stitched or stitched/nano structures were confined at narrow area due to the multistitching. On the other hand, it was observed that the off-axis failure of unstitched/nano or stitched/nano woven E-glass/polyester composite structures showed more brittle behavior.     

Dyeing properties of nylon 66 nano fiber with high molecular mass acid dyes

Research and development of nano fiber products is very active over the world. Physical characteristics and dyeing properties of nylon 66 nano fiber were investigated in this study. X-ray diffraction, DSC, analysis of amino end group, and water absorption were performed to get information concerning physical properties of nano fiber. Nylon 66 nano fiber was dyed with high molecular mass acid dyes. Effects of dyeing temperature, pH of dyeing solution, and concentration of acid dyes on dyeing properties such as rate of dyeing and the extent of exhaustion, were examined and compared to those of regular fiber. It was found that nano fiber adsorbed acid dyes at lower temperature, got rapidly dyed, and its extents of exhaustion at specific dyeing temperature were higher than regular fiber. It was also observed that nano fiber could adsorb a large amount of acid dye without a significant loss in the extent of exhaustion. Washing fastness of the dyed nano fiber was lower by 1/2∼1 grade, light fastness by 1 grade than the dyed regular fiber.     

Warp and weft directional tensile properties of multistitched woven fabric E-glass/polyester nano composites

The aim of this study was to understand the warp and weft directional tensile properties of the developed two dimensional (2D) multistitched multilayer E-glass/polyester woven nano composites. It was found that the warp and weft directional specific tensile strength and modulus of unstitched structure were higher than those of the machine stitched and machine stitched/nano structures due to stitching caused filament breakages. When the nano silica material in the unstitched E-glass/polyester composite structure increased, the warp and weft directional specific tensile strength and the modulus of the unstitched/nano structures increased. The failure of warp and weft directional 2D unstitched and unstitched/nano woven E-glass/polyester composite structures had a complete delamination in their cross-sections. But, the failure of warp and weft directional 2D stitched and stitched/nano woven E-glass/polyester composite structures had a local delamination in their cross-sections and the failure was confined at a narrow area. The warp and weft directional specific damaged areas of unstitched structure were higher than those of the stitched and stitched/nano structures. Also, the warp and weft directional specific damaged areas of machine stitched structure were slightly higher than those of the machine stitched/nano structure. It could be concluded that the addition of nano silica to the stitched structures improved to their damage resistance.