共查询到19条相似文献,搜索用时 93 毫秒
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将高效、绿色的水溶性广谱杀菌剂BCT-2与NH3复配保存鲜天然胶乳(NRL),研究了复合保存剂对NRL保存效果、天然橡胶(NR)的硫化特性和加工性能、NR硫化胶的物理机械性能的影响。结果表明,采用BCT-2/NH_3复合保存剂保存NRL效果良好,尤其是挥发脂肪酸值(VFA NO)在7天内始终维持在0.05以下;NR混炼胶的硫化速率和最大交联度比采用NH_3+TT/ZnO保存时更高;NR混炼胶的加工性能优良,网络结构较NH_3+TT/ZnO保存时更稳定;NR硫化胶的物理机械性能优于采用NH_3+TT/ZnO保存时硫化胶,拉伸强度达到26.23 MPa,撕裂强度达到30.71 k N/m。 相似文献
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本研究采用了0.15%以下的氨含量与一定量的三嗪类广谱抗菌剂-HY复合保存体系的低氨浓缩天然胶乳(以下称低氨胶乳),与NH_3+TMTD/ZnO(即TT/ZnO)复合保存体系的低氨胶乳对比,研究了两大保存体系对低氨胶乳的保存效果影响,测定了预硫化胶乳硫化胶膜物理机械性能。结果表明:采用0.3%~0.4%含量HY的低氨胶乳有较好的保存效果,各项指标变化幅度与乳胶用户质量指标数值较接近,适合于生产胶乳制品,并可提高硫化胶膜撕裂强度的物理性能。研究结果表明了HY在低氨胶乳的研发应用值得推广。 相似文献
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针对无氨天然胶乳胶膜成型时从模具上下滑(简称下滑)的问题,以气球为例研究凝固剂和稳定剂对无氨天然胶乳成膜性能的影响。结果表明:凝固剂中的二价钙盐和附型剂种类及用量并非无氨天然胶乳胶膜下滑的主要影响因素;壁厚较大的胶膜成型过程中,配合胶乳中的氨和氢氧化钾对浸渍在模具上的凝固剂具有膨胀和增稠的作用,有利于阻止成型胶膜下滑,其中氨的作用更为突出;稳定剂中不加氨和氢氧化钾的无氨天然胶乳在成型过程中缺少能使凝固剂在自然条件下产生膨胀和增稠的作用,胶膜与模具的附着力不能随胶乳成型进程而增大,胶膜与模具的附着力小是造成无氨天然胶乳胶膜下滑的主要原因。 相似文献
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天然胶乳鲜胶乳(NRL)若不加入任何保存剂,一般环境下易受细菌感染导致变质腐败,现阶段生产中通常采用0.7%的氨(按胶乳质量计)保存NRL。但随着乙烯利刺激胶树增产,国内天然胶乳质量出现波动,氨水保存效果不显著,对制品一致性也有一定的影响。现今普遍采用的天然胶乳鲜胶乳保存剂有TT/Zn O,以及HY等。TT/Zn O是良好的杀菌剂和抑酶剂,TT引起呼吸作用酶遭受破坏,溶解细胞壁引起细菌细胞质外流,还有一定螯环化作用,干扰细菌正常代谢,影响其生长繁殖;Zn O一方面作为毒酶剂抑制酶的去稳定作用,另一方面与TT反应生成二乙基二硫代氨基甲酸锌(ZDC),协同TT杀菌。然而,TT可能在使用过程中产生致癌的亚硝胺物质,它的存在影响制品的安全。因此低氨甚至是无氨保存体系的研发一直是胶乳工业界的研究热点。本研究采用新型的保存剂G和NH3复合保存天然胶乳鲜胶乳,研究此复合保存体系对鲜胶乳保存效果,通过观察其外在表象,测定挥发脂肪酸值、黏度、p H表征鲜胶乳的保存效果。 相似文献
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进行新型天然胶乳生物保存剂(简称生物保存剂)在标准胶制备中的应用研究,并与传统保存剂氨进行对比。结果表明:随着生物保存剂和氨质量分数的增大,天然胶乳的保存时间延长,当生物保存剂的质量分数大于0.010(按干胶计)时,天然胶乳的保存时间超过10 h;与采用氨保存的天然胶乳制备的标准胶相比,采用生物保存剂保存的天然胶乳制备的标准胶凝固用酸(甲酸)量大幅度减小,回收率较高,灰分含量、杂质含量、挥发分含量和塑性初值较大,塑性保持率和门尼粘度较低,胶料物理性能无明显差异,生产成本较低,生产环境改善。 相似文献
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Ting Wang Hong‐Xing Gui Wen‐Fei Zhang Ke‐Xi Zhang Wei‐Qiang Yu Yi‐Min Li Ri‐Zhong Zeng Mao‐Fang Huang 《应用聚合物科学杂志》2015,132(15)
A derivative of sym‐triazine (HTT) was chosen as a new nonammonia preservative for concentrated natural rubber latex (CNRL) in place of NH3–TT/zinc oxide (ZnO). The preservation effects of the HTT for CNRL, drying characteristics, mechanical properties, and cytotoxicity of the vulcanized natural rubber (NR) film were investigated. The results show that the CNRL was preserved steadily for more than 6 months with 0.3% HTT, and the volatile fatty acid number, viscosity, and mechanical stability of CNRL all met the requirements of ISO 2004:2010(E). The drying characteristics of the vulcanized NR film preserved by HTT retained no change compared with those of the film preserved by NH3–TT/ZnO. The tensile strength and elongation at break of the vulcanized NR film preserved by HTT were 32.17 MPa and 853.80%, respectively; these were very similar to those of the film preserved by NH3–TT/ZnO, whereas the tear strength reached 68.43 kN/m, and this was much higher than that by NH3–TT/ZnO. The results of the cytotoxicity and dermal irritation tests prove that HTT is not especially harmful to humans. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41749. 相似文献
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The presence of Mg2+ ions was found to be a major cause of destabilization of natural rubber (NR) latex. On the other hand, the addition of excess PO ions to remove Mg2+ ions could adversely affect the physical properties of dipped products made of NR latex. A series of concentrated latex samples were treated with varying amounts of Mg2+ and PO ions. Changes with time in the characteristics of the treated latex samples such as mechanical stability time, volatile fatty acid number, and chemical stability time and in the physical properties of the dipped products such as aged and unaged tensile properties were monitored. The latex batch with a PO ion concentration of 30 ppm was found to produce the best‐quality latex and dipped products. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3120–3124, 2006 相似文献
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Epoxidized natural rubber (ENR) was prepared via in situ epoxidation from high ammonia concentrated natural rubber latex with formic acid and hydrogen peroxide in the presence of a surfactant at 50°C for 4, 8, and 12 h. The obtained ENRs containing 20, 45, and 65 mol % of expoxide groups were denoted ENR20, ENR45, and ENR65, respectively. The differential scanning calorimetric study revealed that they exhibited higher glass transition temperatures than that of natural rubber (?62.4°C), at ?38.2°C for ENR20, ?27.8°C for ENR45, and ?19.7°C for ENR 65. It was clearly seen that their glass transition temperatures increased as the amount of epoxide groups increased. The prepared ENRs were compounded and vulcanized to prepare test specimens for determination of oil resistance and various physical properties. It was found that the swelling of ENRs in oils was substantially less than that of natural rubber. The oil resistance of ENR65 was comparable to that of nitrile rubber, commonly used as oil resistant rubber. ENR65 also showed higher hardness than other ENRs. Contrarily, ENR20 possessed superior tensile strength and compression set when compared with other ENRs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3948–3955, 2006 相似文献
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《应用化工》2022,(5)
采用单独含有NH_3、HY的天然橡胶作为对照样,与含有复合保存剂HY/NH_3的天然橡胶进行性能比较,利用红外光谱仪测定天然橡胶结构,橡胶加工分析仪测定其加工性能,核磁共振交联密度仪测其交联密度,研究复合保存剂HY/NH_3对天然橡胶性能的影响。结果表明,HY/NH_3几乎不影响生胶结构;在应变、温度扫描环境下,NY-1的弹性模量G’最大,损耗因子tanδ最小,NY-3居中;在频率扫描环境下,NY-3的弹性模量G’最大,损耗因子tanδ居中,NY-1的弹性模量G’居中,损耗因子tanδ最小;三种扫描环境下,NY-2的弹性模量G’均最小,损耗因子tanδ均最大;老化前,复合保存剂样品的总交联密度小于NH_3、HY样品的总交联密度;老化后,所有样品的总交联密度均变小。 相似文献
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S. P. Vernekar M. B. Sabne S. D. Patil A. S. Patil S. B. Idage C. V. Avadhani S. Sivaram 《应用聚合物科学杂志》1992,44(12):2107-2114
Effect of latex concentration on the extent of epoxidation and physical properties of epoxidized natural rubber (ENR) was evaluated as a function of latex concentration in the range of 20–60% by weight. The epoxidation rate increased with increasing latex concentration. Physical properties and sequence distribution of an epoxy group of ENR with 30 mol % epoxy content was invariant with the latex concentration employed for epoxidation. 相似文献
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Natural rubber latex layered clay nanocomposites were prepared with low loadings of nanoclay using conventional compounding technique. A higher loading of clay resulted in processing difficulties due to viscosity build up. X‐ray analysis showed that nanocomposites in which layered silicate layers were either delaminated or ordered as in an intercalated structure was obtained. Partially exfoliated structure was observed from TEM photographs of nanocomposites with 3 phr nanoclay. The transport properties, sorption, diffusion, and permeation coefficients were measured using the solvent toluene at 303 K. A higher decrease for the diffusion coefficient for nanocomposites directs the presence of tortuous path for the diffusing molecules. Thermodynamic parameters show a better compatibility for the silicates with rubber resulted in the formation of an elastomeric network. Gas permeability results of the nanocomposites suggest a better barrier resistancefor oxygen molecules even in lower loading of nanoclay and different gas transport models (Nielsen, Bharadwaj, Cussler) were applied to describe the behavior of these nanocomposites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献