共查询到20条相似文献,搜索用时 187 毫秒
1.
2.
对天然胶乳及生胶所制备的硫化胶进行网络结构和性能测试 ,考察不同加工方法对硫化胶结构与性能影响。结果表明 ,胶乳胶膜的交联速率、效率、硫化胶强度及耐老化性能都比相应干胶的大 ;对普通硫化体系 ,生胶硫化胶的单、双硫键密度占总交联键密度的比例随硫化时间的延长有较大幅度增加 ,而配合胶乳胶膜的则变化不明显。 相似文献
3.
4.
制备工艺对NR性能的影响 总被引:1,自引:1,他引:0
采用新鲜天然胶乳分别制备乙酸凝固NR(NR-1)、微生物凝固NR(NR-2)、乙醇胺混合微生物凝固NR(NR-3)和蛋白酶混合自然凝固NR(NR-4),研究制备工艺对NR性能的影响。结果表明:NR-1和NR-2生胶的耐热老化性能和热稳定性好于NR-3和NR-4生胶;NR-4胶料的MH最大,t90最短,NR-3胶料的MH较小,t90最长;NR-4硫化胶的定伸应力和拉伸强度较大,拉断伸长率较小,NR-1硫化胶的定伸应力和拉伸强度较小;NR-4生胶、混炼胶和硫化胶的弹性转矩(S′)和剪切储能模量(G′)最大,损耗因子(tanδ)最小,NR-1生胶、混炼胶和硫化胶的S′和G′最小,tanδ值最大。 相似文献
5.
6.
7.
8.
9.
采用酶辅助微生物凝固鲜胶乳提高天然橡胶产品性能,探究了酶用量对天然橡胶理化指标、硫化特性、加工性能、力学性能、机理及生热性能的影响。结果表明,随着酶用量的提高,生胶塑性初值和门尼黏度升高,塑性保持率降低;硫化胶正硫化时间(t90)和焦烧时间(t10)变短;生胶的弹性模量(G′)高,损耗因子(tan δ)小;硫化胶的拉伸强度、100%定伸应力及撕裂强度均呈上升趋势,老化处理后,硫化胶的力学性能同样保持升高的趋势;同时硫化胶温升呈下降趋势;此外,氮含量和凝胶含量有降低趋势,而丙酮溶物含量有升高趋势。 相似文献
10.
采用环保型抑菌、杀菌剂BCT-2与氨(NH_3)复配作为鲜天然胶乳的新型复合保存剂,研究其对鲜天然胶乳保存效果、天然橡胶(NR)生胶6项指标、混炼胶硫化特性以及硫化胶物理性能的影响。结果表明:复合保存剂BCT-2/NH_3对鲜天然胶乳的保存效果优于NH_3和NH_3+TMTD/氧化锌,保存144 h后鲜天然胶乳的挥发脂肪酸值在0.05左右,粘度在10mPa·s左右,pH值高于9;相应NR生胶的塑性初值、塑性保持率和门尼粘度均小于NH_3保存试样;随着BCT-2的加入,混炼胶的最小转矩、最大转矩、焦烧时间和正硫化时间与氨保存试样相比均有一定程度的降低和缩短;而复合保存剂BCT-2/NH_3对硫化胶物理性能影响不大。 相似文献
11.
分别以丙二醇、一缩二乙二醇、丙三醇处理纳米SiOx,研究了纳米SiOx在天然乳胶及PVA复合天然乳胶体系中的均匀分散技术;性能测试结果及SEM照片表明:①采用多羟基有机化合物作为表面处理剂,可以使纳米SiOx在胶膜中分散均匀.并有效防止其在体系中的聚集。②多数试样的拉伸强度和撕裂强度均高于添加常规补强剂(白炭黑或炭黑)的试样。③采用一缩二乙二醇作为纳米SiOx表面处理剂的天然乳胶膜,其拉伸强度为59.44MPa,撕裂强度为27.66N/mm,综合力学性能最优,分别比添加白炭黑的试样提高了44.6%和33.2%。 相似文献
12.
Calcium carbonate/natural rubber (NR) latex nanometer composites were prepared by adding nanometer CaCO3 whose surface had been treated to natural rubber latex (NRL) before sulfuration. The physical, thermooxidative aging, and thermal degradation properties and the ultra‐microstructure were analyzed with a multipurpose material testing meter, a thermal analysis meter and a Philips XL‐30 SEM, respectively. The results showed that the structures and properties of nanometer composites could be clearly improved by NRL mixed with surface‐treated nanometer CaCO3. The physical properties of the nanometer composites were best when the content of surface treatment agent was 2.5% (to nanometer CaCO3), the nanometer CaCO3/NRL content was 3:100, and the stirring time for treating the surface of the nanometer CaCO3 was 20 min. Simultaneously, the thermooxidative aging resistance of the nanometer composites also was significantly improved. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3442–3447, 2006 相似文献
13.
The technique of enzyme treatment on the water‐soluble proteins and mechanical properties of natural rubber latex (NRL) films was studied. The main aim was to introduce an enzymic catalysis method to tackle the protein allergy problem in NRL product. The suitable pH value, the temperature, and the best proportion of transglutaminase to deal with NRL were found. The protein spillage of modified NRL films was greatly lower than that of unmodified NRL, and the tensile strength and the elongation at break of the modified NRL films almost had been scarcely changed. The compactness of the NRL films was improved simultaneously. These suggest that the modified NRL can be used as a kind of latex with low‐allergy personal barrier products such as surgical gloves. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
14.
Vihanga Thejasri Ambegoda Shantha Maduwage Egodage Frank Dennis Blum Madhubhashini Maddumaarachchi 《应用聚合物科学杂志》2021,138(12):50047
Enhancement of the hydrophobic nature of natural rubber latex (NRL) films will open up a wide range of applications for them. Incorporating hexadecyltrimethoxysilane treated superhydrophobic diatomaceous earth (DE) in NRL, resulted in films with increased hydrophobicity. The nano-scale surface roughness for the superhydrophobic surface was provided by DE and low surface energy was achieved by treating DE with hexadecyltrimethoxysilane (treated DE). Surface wettability and morphology were analyzed by water contact angle (WCA) measurements and scanning electron microscopic analysis, respectively. About 38% wt/wt hexadecyltrimethoxysilane to DE ratio could make superhydrophobic DE with WCAs larger than 150°. A dispersion of treated DE was incorporated into NRL resulting in hydrophobic NRL films possessing WCAs greater than 110° with 41% treated DE particle loading. The resulting NRL films were harder and had smaller tensile strength compared to normal NRL film. 相似文献
15.
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 相似文献
16.
以甲基丙烯酸羟乙酯(HEMA)作为天然胶乳(NRL)的接枝改性剂,采用乳液聚合法制备了NR-g-HEMA[HEMA接枝NR(天然橡胶)]胶乳;然后以此为基体,并以水溶性松香树脂为增黏树脂、邻苯二甲酸二丁酯(DBP)为增塑剂等,制备相应的NR-g-HEMA胶粘剂;最后,用该胶粘剂压制胶合板,并对胶合板的粘接性能进行了测定。结果表明:采用单因素试验法优选出制备NR-g-HEMA胶乳的最佳工艺条件为m(干态单体)∶m(NRL)∶m(引发剂)∶m(活化剂)∶m(交联剂)=20∶100∶0.2∶0.2∶0.1、反应时间为8 h和反应温度为16℃,此时相应胶合板的剪切强度(1.88 MPa)符合Ⅲ类胶合板的指标要求。 相似文献
17.
This study aims to investigate the viability of employing corn-based fillers (powdered corn grain [CG], corn flour [CF] and cornstarch [CS]) to improve the biodegradability of natural rubber latex (NRL) composites by varying filler loading from 0 to 50 phr. Notable variation in both physical and mechanical properties were observed for the different filler types, with CG-filled NRL demonstrating the better adhesion with NRL. Thus, CG-filled composites were selected for investigation of biodegradability. Increased CG loading in NRL compounds enhanced biodegradation; with over 70% degradation observed for 50 phr CG loading upon 15 weeks of soil burial. However, the trade-off between mechanical properties and biodegradability limits the CG loading in the NRL matrix to 20 phr for manufacturing NRL-based products. It was observed that NRL with CG filler loading of 20 phr conforms to the ASTM D3578 standard for manufacturing rubber gloves; with 50% biodegradation upon 15 weeks of soil burial. 相似文献
18.
19.
N. C. Dafader M. E. Haque F. Akhtar M. U. Ahmad 《Polymer-Plastics Technology and Engineering》2013,52(7):889-892
Blend rubber films were prepared by mixing styrene grafted rubber latex and natural rubber latex (NRL) with varying proportions by gamma radiation from Co-60 source at room temperature. Tensile strength, modulus at 500% elongation, elongation at break, permanent set, and swelling ratio were measured. Tensile strength and modulus at 500% elongation attain maximum at 8 kGy radiation dose for blend rubber films. The increase in tensile strength is insignificant, but modulus increases from 5.61 to 7.46 MPa with increased proportion of grafted rubber latex from 40 to 70% in the blend at this radiation dose. Elongation at break, permanent set, and swelling ratio of blend rubber decreases with increase in radiation dose as well as proportion of grafted rubber. 相似文献
20.
A means is developed for forming polysaccharide-based composites with useful material properties through use of unmodified and chemically modified natural rubber latex (NRL). Starch was used as a model for polysaccharides. The NRL was modified by grafting with dimethylaminoethyl methacrylate (DMAEMA) to form a latex with cationic water-soluble polymeric ‘hairs’ of polyDMAEMA, which should form hydrogen bonds with starch. Starch solutions, containing 20% glycerol as a film-forming aid, and the modified NRL were mixed and films allowed to form. The unmodified latex acted only as filler in the starch films, but with modified NRL, the mechanical properties of the films were significantly altered. The elastic modulus was greatly decreased and strain at break greatly increased. The glass transition temperature increased from −48 °C to −32 °C, suggesting significant compatibilization. Freeze-fracture TEM micrographs indicate strong interactions between the surface of the modified NRL and starch. The polyDMAEMA chains are more hydrophilic than the starch, and the addition of grafted latex results in a 20° drop of the water contact angle of the formed film, and a 25% increase of the water absorption compared to the native starch; with unmodified NRL, the opposite effect was observed. 相似文献