改性天然胶乳应用于玻纤橡胶基布表面浸胶处理的研究

叙述利用环氧化改性天然乳胶配制浸胶浆进行玻纤橡胶基布表面浸胶处理．处理布用于矿山导风简和夹布胶管增强基布。并对处理布的强力，制品的布与布、布与胶的层间附着力进行了评价。     

环氧化天然胶乳用于玻璃增强水泥基布处理

应用环氧化改性天然胶乳（ＥＮＲＬ）及耐碱性树脂为基料进行玻璃纤维网络增强水泥基布抗碱、定形涂覆处理,并对处理布的经纬线稳定性及耐碱性进行评价。     

用天然胶乳制备氯化橡胶工艺

天然胶乳制备氯化橡胶，反应条件较温和，克服了传统方法的缺点，解决环保问题。     

天然胶乳的化学改性

简要介绍了天然胶乳化学改性的有利条件，化学改性天然胶乳的主要品种、相关技术及其应用以及仍存在的主要问题。     

天然胶乳的合成改性

天然胶乳以及用成膜法将其制成的聚合物 ,具有某些合成材料无法比拟的宝贵性能 ,其中包括全顺式聚异戊二烯提供的物理性能。但是这种材料也有某些缺点。例如 ,用作压敏粘合剂时 ,如果干燥后聚合物受热 (如在激光打印机中 ) ,有时会失去粘合性能。此外 ,由于蛋白质过敏问题 ,使得天然胶乳在外科手术手套和避孕套中的应用越来越受到限制。本文提出了解决这些问题的方法。天然胶乳被用作一种人造聚合物进行第二步游离基乳聚的种子。在进行此种聚合时 ,必须注意或是通过确保可代替蛋白质的聚合物组分接枝到胶乳粒子外部 ,或是通过确保能改善聚合…     

环氧化天然胶乳用于玻纤增强水泥基布处理

应用环氧化改性天然胶乳（ＥＮＲＬ）及耐碱性树脂为基料进行玻璃纤维网格增强水泥基布抗碱、定形涂履处理,并对处理布的经纬线稳定性及耐碱性进行评价。     

天然胶乳共混改性的研究进展

概述天然胶乳/天然高分子(包括壳聚糖、淀粉、纤维素和丝素蛋白质)共混、天然胶乳/合成胶乳共混、天然胶乳/合成乳液共混和天然胶乳/纳米材料共混等不同改性方法的研究进展.由于天然胶乳制品的耐油、耐老化等性能不佳,为扩大天然胶乳使用范围,有必要对胶乳进行物理改性或化学改性,使天然胶乳朝高性能化方向发展.     

氧化石墨烯改性天然胶乳的优化试验

采用氧化石墨烯对天然胶乳进行改性,通过正交试验方法探讨氧化石墨烯用量、硫化体系及硫化工艺参数对改性胶乳硫化胶膜强度性能的影响。结果表明:在试验范围内,以拉伸强度和撕裂强度为考察指标,氧化石墨烯改性天然胶乳的优化方案氧化石墨烯用量为0. 125份,硫黄用量为1份,氧化锌用量为0. 4份,促进剂PX用量为1份,硫化温度为75℃,硫化时间为1 h;优化方案验证试验的硫化胶膜拉伸强度为28. 83 MPa,撕裂强度为65 kN·m~(-1),与未添加氧化石墨烯的空白样相比分别提高了45. 83%和51. 16%,表明氧化石墨烯对天然橡胶有良好的补强效果。     

Effect of temperature on sulfur prevulcanization of natural rubber latex

Sulfur prevulcanization of natural rubber latex was conducted at 60, 70, 80, and 90°C for different periods. The extent of crosslinking was assessed. Tensile properties, water absorption, leaching, and stress-relaxation characteristics of the films were also evaluated. The volume fraction of rubber (Vr), which is a measure of crosslink density of the films, showed a maximum when prevulcanization was conducted at 80°C for 2 h or at 90°C for 1 h. At lower temperatures, the rate of reaction was slow. At each temperature, tensile strength and elongation at break decreased when the prevulcanization time increased, whereas the modulus increased up to a maximum crosslinking and thereafter decreased. Water absorption and leaching were more rapid in prevulcanized film than in postvulcanized film. The rate of stress relaxation slightly increased as the extent of prevulcanization increased. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 1913–1920, 1997     

Noncatalytic hydrogenation of natural rubber latex

Hydrogenation is an important method of chemical modification, which improves the physical, chemical, and thermal properties of diene‐based elastomers. Natural rubber latex (NRL) could be hydrogenated to a strictly alternating ethylene–propylene copolymer using diimide generated in an in situ system. The diimide generated using the in situ technique for hydrogenation of NRL was accomplished by thermolysis of p‐toluenesulfonyl hydrazide (TSH). A molar ratio of TSH to double bonds equal to 2 : 1 was found to be the optimum ratio to provide a high percentage of hydrogenation. 95% Degree of saturation of NRL was achieved in o‐xylene. Hydrogenated products are characterized by FTIR and NMR spectroscopy. The thermal stability of hydrogenated rubber was improved as shown from the results of thermogravimetric analysis. From the differential scanning calorimetry measurement, the glass transition temperature of the hydrogenated product did not appear to change. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2885–2895, 2007     

丝胶接枝物改性天然乳胶的研究

利用丝胶优良的抗氧化性和亲肤性等特点,将丝胶包覆在天然乳胶粒表面,从而隔绝了天然乳胶膜与皮肤的直接接触,改善天然乳胶制品对皮肤的过敏性反应,使其不仅具有耐氧化性,而且与皮肤接触后可有效防止肌肤干燥,抑制肌肤黑色素生成等。同时将水性聚氨酯通过先接枝后杂凝聚的方法,在不改变乳胶断裂伸长率的情况下,提高拉伸强度,实现了对天然乳胶过敏性和机械性能的双重改善。     

弱酸铵盐保存天然鲜胶乳的研究

通过对弱酸铵盐性质的分析，探索弱酸铵盐对鲜天然胶乳的保存效果及其性能的影响。实验结果表明，浓度越高的碳酸铵盐溶液的保存体系，其缓冲能力越大．越能很好地中和细菌代谢产生的脂肪酸．以防止天然胶乳的迅速凝固，保存效果越好。综合考虑经济和社会效益，碳酸铵可作为天然胶乳的保存剂，最佳质量分数为1．8％，其硫化胶力学性能得到部分改善，可以代替传统的氨水保存剂，降低污染，提高经济效益，改善工厂作业环境。     

三氯溴甲烷改性天然胶乳的研究

用三氯溴甲烷改性天然胶乳，研究了反应时间、反应温度、三氯溴甲烷的用量等对改性胶乳的硫化胶膜物理机械性能的影响，利用DSC对产物进行了分析。结果表明，反应时间为10h，反应温度在35℃时，所得胶膜物理机械性能较好；随着三氯溴甲烷用量的增加，改性天然胶乳的硫化胶膜物理机械性能下降：三氯溴甲烷改性天然胶乳的玻璃化温度高于未改性天然胶乳。     

Study on preparation of chlorinated natural rubber from latex and its thermal stability

The effects of pH value of reaction system, reaction time, and reaction temperature on the chlorination reaction in the preparation of chlorinated natural rubber (CNR) from natural rubber latex were discussed. It has been found from the thermal analysis that the thermal degradation of CNR in nitrogen is a one-step reaction, and 30% carbonide with a stable structure remained at 360 to 700°C; whereas the thermo-oxidative degradation of CNR in air is a multistep reaction, and the thermal degradation ratio reaches to 100% at 560°C. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2863–2867, 1999     

磷脂对浓缩天然胶乳机械稳定性的影响

在天然胶乳中添加磷脂,研究磷脂对天然胶乳机械稳定性的影响,结果表明,随着磷脂用量和氨含量的增加,天然胶乳的机械稳定度逐渐升高。气相色谱-质谱联用仪(GC-MS)分析表明,磷脂在碱性条件下水解产生亚油酸、棕榈酸、油酸、反油酸、硬脂酸、α-亚麻酸等长链脂肪酸,进一步与氨水反应形成脂肪酸铵,并吸附在橡胶烃粒子表面,提高了天然胶乳的机械稳定性。随着碱度的升高和水解时间的延长,磷脂水解产物的化学组成和含量存在一定差异。     

热裂解气相色谱法测定天然胶乳中的干胶含量

研究热裂解气相色谱法测定天然胶乳中的干胶含量。试验结果表明,干胶含量与裂解主要产物峰面积呈现良好的线性关系,采用标准曲线法测定天然胶乳中的干胶含量,重复测定的相对标准偏差为0.14%,与国标法的平均相对误差为1.51%,定量分析结果准确,操作简便。     

淀粉纳米晶对天然胶乳性能的影响

将淀粉纳米晶作为天然胶乳的补强剂,研究其对天然胶乳的胶体性能及硫化胶膜的物机性能、耐水性和耐溶剂的影响。研究结果表明:将淀粉纳米晶加入天然胶乳后,胶乳的粘度变化不大,机械稳定度提高;硫化胶膜的物机性能明显提高,耐溶剂性提高,而耐水性降低。     

Reinforcement of natural rubber latex film by ultrafine calcium carbonate

Using ultrafine calcium carbonate to reinforce natural rubber latex film, the effect of its content on latex properties such as surface tension, viscosity, mechanical stability, and heat stability and the physical properties of latex film before and after aging such as tear strength, modulus, and tensile strength were investigated. The results showed that the surface tension of natural rubber latex reinforced by ultrafine calcium carbonate only changed slightly; when the content of calcium carbonate was less than 20%, the change of viscosity was not obvious, but when the content was greater than 20%, the viscosity significantly lowered. Ultrafine calcium carbonate could effectively improve the tear strength, tensile strength, and modulus of the natural rubber latex film. The modulus increased with the increment of the calcium carbonate. When the content of calcium carbonate was less than 15%, the tear strength and tensile strength increased with the increments of calcium carbonate, but when the content was greater than 15%, the above‐mentioned properties decreased with the increment of calcium carbonate. By comprehensive consideration, the best reinforcing effect was obtained at a content of 15% ultrafine calcium carbonate. The particle diameters of calcium carbonate and their distribution in the calcium carbonate emulsion and in the rubber film were analyzed with SEM and a laser particle size tester, which showed that the distribution of calcium carbonate in the latex film was even and that it could effectively reinforce natural rubber latex film. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 982–985, 2003