共查询到19条相似文献,搜索用时 99 毫秒
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以玉米淀粉、聚乙烯醇(PVA)为主要原料,采用酸碱处理法制备了淀粉胶粘剂;然后用异氰酸酯进行改性,制备了木材用复合淀粉胶粘剂。研究结果表明:碱处理能影响淀粉间的氢键强度,酸处理时间相同时,随着碱处理时间的延长,淀粉的羟基峰均向长波数方向移动,羟基移动波数和复合淀粉胶粘剂的胶接强度均呈先升后降态势,碱处理40 min后复合淀粉胶粘剂的胶接强度(1.345 MPa)相对最大;淀粉胶粘剂的结晶度和耐热性随碱处理时间延长呈先降后升态势,碱处理40 min时淀粉的结晶度降低了10.6%,初始热降解温度降低了15%;碱处理能腐蚀淀粉颗粒表面,碱处理20 min时淀粉颗粒的被腐蚀程度相对最低,而PVA与淀粉的包覆效果在碱处理40min时相对最佳。 相似文献
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表面处理对硅橡胶胶粘剂胶接性能的影响 总被引:9,自引:0,他引:9
本文着重研究了不同表面处理条件下硅橡胶胶粘剂的粘接性能。有机硅烷偶联剂对提高硅橡胶胶粘剂的粘接性能有显著效果,其中以GPJ-43的处理效果为最佳。铝合金试样机械打磨后采用不同溶剂清洗对粘接性能也有影响,其中以三氯乙烯的效果为最好。磷酸阳极化是很有效的表现处理方法。对铝-铝粘接界面的分析发现,硅橡胶胶粘剂粘接接头的破坏一般为胶粘剂的内聚破坏或胶粘剂与偶联剂界面的粘附破坏。 相似文献
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胶合板用大豆蛋白基胶粘剂具有原料来源广、可再生、价格低廉和无甲醛释放等优点,但其仍存在储存时间短、易霉变等缺点。采用单因素试验法探讨了防霉剂种类及含量对大豆蛋白基胶粘剂储存时间和胶合板耐霉变性能的影响。结果表明:当胶液中w(防霉剂C)=1.00%、胶液储存时间为1~14 d时,胶合板经28℃/相对湿度92%霉变处理42 d后,其胶接强度分别为0.85 MPa(比无霉变处理体系降低15%,此时胶液储存1 d)、0.88 MPa(比无霉变处理体系提高42%,此时胶液储存14 d)或变化不大(胶液储存4~10 d),说明含防霉剂C胶液的防霉耐久性相对最好。 相似文献
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Effects of AOT reverse micelle extraction on structure and emulsifying properties of soybean protein
Lifen Zhang Mingzhu Zhang Xiaoyang Sun Fusheng Chen Qian Wu 《Journal of the American Oil Chemists' Society》2021,98(9):923-932
The present study aimed to investigate the forward and backward extraction efficiency, structure, and emulsifying properties of soybean proteins obtained through bis (2-ethylhexyl) sulfosuccinate sodium salt (AOT) reverse micelle, as well as their relationship. The results showed that the extraction efficiency was the highest with the forward extraction time of 25 min, pH of 3.0, temperature of 45°C, KCl concentration of 0.0 mol L−1, and the backward extraction time of 10 min, pH of 4.0, temperature of 30°C, KCl concentration of 0.5 mol L−1. Significant changes in the secondary structure and fluorescence intensity of soybean protein after AOT reverse micelle extraction were observed. More β-sheet structure and higher fluorescence intensity corresponded to the higher emulsion stability of soybean protein. The results indicated that reverse micelle extraction shows great application in food industry. 相似文献
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Soy proteins have shown great potential for adhesive and resin applications. This investigation characterized the thermal
and adhesive properties of the major soy protein components conglycinin (7S) and glycinin (11S) after chemical modification.
These globulins were extracted from defatted soy flour, then modified with either sodium hydroxide, sodium dodecyl sulfate
(SDS), or urea. Modified 7S, 11S, and mixtures of 7S and 11S at varying ratios were evaluated for gluing strength with cherry
veneer plywood and for thermal denaturation using DSC. Adhesive strength and water resistance were significantly improved
for all proteins modified with sodium hydroxide. Gluing strength and water resistance were improved for SDS- and ureamodified
proteins containing greater portions of 7S globulins. The opposite behavior was observed for proteins containing large amounts
of 11S globulins. DSC results showed that the temperatures of denaturation (T
d
) decreased for the proteins modified with sodium hydroxide or urea, whereas the T
d
values of proteins modified with SDS were similar to the unmodified proteins. These results suggested that, at the concentrations
studied, sodium hydroxide or urea could denature soybean protein more effectively than SDS, resulting in lower protein thermal
stability. Soybean proteins with high ratios of 11S had more ordered structures, as evidenced by the high enthalpy values
of protein denaturation observed in DSC measurements. 相似文献
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通过FTIR、元素分析、GPC对4种不同来源的木质素磺酸钠进行物理化学性质分析,并将其与水性聚酰胺协同改性豆粕胶黏剂(简称豆粕胶),利用测试接触角、剪切黏度和湿态胶合强度考察改性前后胶黏剂的浸润性、流变特性以及所得胶合板的胶合性能.红外谱图分析表明,在1065 cm–1附近出现了磺酸基或磺甲基中S==O的伸缩振动吸收峰,证明木质素经过磺化反应或磺甲基化反应得到木质素磺酸钠;木质素磺酸钠中磺酸基含量越高,经其改性的豆粕胶的零剪切黏度越低且在木材表面的润湿性越好;豆粕胶黏剂与杨木单板的接触角从未改性的95°降到改性后的61°;与水性聚酰胺协同改性后的豆粕胶制得胶合板的湿态胶合强度达到0.92 MPa,合格率为100%,满足国家Ⅱ类胶合板的标准要求(胶合强度≥0.70 MPa,合格率≥90%). 相似文献
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以黏附剂种类及含量作为试验因素,以预涂厌氧胶A组分和预涂螺栓的外观、预涂螺栓装配时的状态、初固时间和扭矩强度等为考核指标,采用单因素试验法优选出制备预涂厌氧胶的最优方案。研究结果表明:当PVP(聚乙烯吡咯烷酮)-K30为黏附剂、w(PVP-K30)=2.0%(相对于厌氧胶总质量而言)时,预涂厌氧胶的综合性能相对最好。 相似文献
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Masayuki Yamaguchi 《应用聚合物科学杂志》1998,70(3):457-463
Adhesion properties between branched polyethylene (PE) and isotactic polypropylene (PP) were studied by a peel test and scanning electron microscopy. In this study, two types of branched PEs were used; one is a linear low density polyethylene (LLDPE) and the other is a high pressure low density polyethylene (LDPE). The adhesive strength of the LLDPE/PP is much higher than that of LDPE/PP. Furthermore, the formation of PE influxes between PP spherulites has a small effect on the adhesion. The dynamic viscoelastic measurements for the binary blends composed of branched PE and PP were also carried out to estimate the interfacial tension by using a rheological emulsion model proposed by Palierne. The interfacial tension is 1.0 mN for LLDPE/PP and 2.1 mN for LDPE/PP, suggesting that the interfacial thickness of LLDPE/PP is about twice that of LDPE/PP. The adhesive strength between branched PE and PP will be determined by the interfacial thickness, which represents the entanglements between two polymers. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 457–463, 1998 相似文献
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采用苯乙烯-丁二烯-苯乙烯(SBS)和苯乙烯-异戊二烯-苯乙烯(SIS)嵌段共聚物,并配合极性的环氧化SBS(ESBS)和环氧化SIS(ESIS)作为基体材料,制备了环氧化SDS(苯乙烯系热塑性弹性体)型热熔压敏胶。研究了ESBS和ESIS用量对压敏胶的初粘力、持粘力和在不同极性底材上剥离强度的影响。结果表明,随着ESBS和ESIS用量的增加,压敏胶的初粘力和持粘力下降,在聚乙烯(PE)上的剥离强度下降,但在聚氯乙烯(PVC)和不锈钢上的剥离强度先增加后下降。当ESBS和ESIS的质量份数均为20份时,压敏胶的初粘力和持粘力分别为23#和43.6 h,在PVC和不锈钢底材上的剥离强度分别达到0.82 N/mm和1.10 N/mm。 相似文献