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在简单均相体系下,研究了壳聚糖及双胍基苯甲酰壳聚糖在双氧水中的降解特性。采用高效凝胶渗透色谱法测量了降解过程中壳聚糖及双胍基苯甲酰壳聚糖的分子量变化,讨论了该体系下双胍基苯甲酰低聚壳聚糖及双胍基苯甲酰壳聚糖的胍基化取代度的变化,通过红外光谱分析了低分子量双胍基苯甲酰壳聚糖结构。结果表明,在降解反应温度为65℃、H2O2质量百分浓度为3.0%、盐酸浓度为1.0%时,反应时间的延长会导致低聚壳聚糖或对双胍基苯甲酰壳聚糖低分子化产物相对分子量的逐渐降低,胍基化取代度也随之降低;红外光谱表明,采用该降解体系制备的降解产物主链结构基本没有发生变化。 相似文献
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超级胍胶是一种应用最先进的工艺精细生产加工的天然胍胶增稠剂,为了更好的发挥超级胍胶的性能,对其高分子结构进行了表征、对其分子量进行了测定,同时,表征了超级胍胶高分子溶液网络结构,并阐述了分子结构的特点及其对压裂液性能的影响。通过优选低水不溶物含量、低使用浓度的新型压裂液增稠剂超级胍胶,可有效降低压裂液残渣含量,减小对储层渗透率及裂缝导流能力的伤害。 相似文献
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蛋白变性剂对多聚半乳糖醛酸酶及其化学修饰酶催化活性的影响 总被引:1,自引:0,他引:1
为了探索几种蛋白质变性剂对多聚半乳糖醛酸酶的作用效果,以水溶性低分子量壳寡糖(COS,分子量约5000)作为修饰剂对已纯化的多聚半乳糖醛酸酶(PG)进行化学修饰,得到纯化的化学修饰酶(COS-PG),然后,测定不同蛋白变性剂(尿素、盐酸胍、SDS和苯酚)对纯化的PG和COS-PG催化活性的影响。结果表明,修饰后COS-PG的比活性是340.10 U(mg protein)1,比修饰前的PG提高了153%,COS-PG的糖含量比PG提高了43.11%,COS-PG的氨基修饰率为32.85%。SDS(十二烷基硫酸钠)、苯酚对PG和COS-PG活性有抑制作用,1 mmol L 1的SDS分别抑制了PG和COS-PG活性的80.99%和91.14%。10 mmol L 1的苯酚分别抑制了PG和COS-PG活性的34.08%和32.70%。低浓度的尿素和盐酸胍对PG有激活作用,5 mmol L 1的尿素使PG活性提高157.79%,3 mmol L 1的尿素使COS-PG的活性提高67.32%。2 mmol L 1的盐酸胍使PG活性提高57.64%,1 mmol L 1的盐酸胍使COS-PG的活性提高5.76%。 相似文献
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《精细与专用化学品》2018,(10)
以1,6-己二胺盐酸盐和1,6-双氰基胍基己烷为原料,水为溶剂,盐酸为催化剂合成了聚六亚甲基双胍盐酸盐(PHMB)。用紫外分光光度法对产物进行了表征。研究了原料1,6-己二胺盐酸盐与1,6-双氰基胍基己烷物质的量比、水的用量、催化剂、反应温度、反应时间对产物收率的影响,得出了最优条件:n(1,6-己二胺盐酸盐):n(1,6-双氰基胍基己烷)=1:0.95,m(1,6-己二胺盐酸盐):m(水)=1:1,盐酸为催化剂、反应温度为160℃、反应时间为5h。在该条件下,PHMB的分子量可以达到2600,收率为98.4%。 相似文献
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《应用化工》2022,(5):1168-1172
胍胶压裂液是低渗透油藏水力压裂应用最广泛的压裂液体系,针对其破胶不彻底,残渣、残胶易造成压后储层伤害的问题,通过耐温耐剪切性、破胶液黏度、破胶液残渣含量测试实验,从10种破胶剂、9种降解剂中筛选、优化了胍胶压裂液复合破胶降解剂。并利用凝胶渗透色谱仪和激光粒度仪对胍胶压裂液破胶液中聚合物分子量和残渣粒径进行了测试。结果表明,0.06%(质量浓度)破胶剂P4(过硫酸铵∶亚硫酸钠=9∶1,质量比)+0.009%降解剂M2(BAT-2)为最佳复合破胶降解剂体系,其对应胍胶压裂液耐温耐剪切性测试稳定黏度、破胶液黏度、破胶液中残渣含量分别为103 mPa·s, 1.5 mPa·s和202 mg/L。相对于现用过硫酸铵破胶剂,优化的破胶降解剂体系可降低破胶液中聚合物平均分子量16.0%;减小破胶液中残渣粒径中值21.5%。 相似文献
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通过在不同工艺条件下超高分子量聚乙烯聚合的小试试验,探讨了聚合压力、温度、催化剂浓度、助催化剂浓度以及搅拌速度等因素对超高分子量聚乙烯的影响。实验表明,各种工艺条件对超高分子量聚乙烯的分子量和机械性能有着不同程度的影响,其中以温度对分子量的影响最大;另外超高分子量聚乙烯的分子量和机械性能也存在着一定的关系。 相似文献
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用聚丙烯酰胺合成氧肟酸型高分子絮凝剂,研究了温度、聚丙烯酰胺分子量、原料物料此、反应时间对反应的影响。实验结果表明:聚丙烯酰胺改性最佳反应温度是30℃,聚丙烯酰胺/盐酸羟胺(摩尔比)为1:1.5,反应时间为8h,聚丙烯酰胺分子量为3×10^6~6×10^6。 相似文献
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In this study, agrochemical was produced from waste polyesters. Reactions of waste polyesters [poly (ethylene terephthalate) (PET) and poly (butylene terephthalate) (PBT)] powder with ethylene glycol (EG) in the presence of tetrahydrofurane (THF) using 0.003 mol lead acetate as a catalyst were carried out in a batch reactor at 470 K and at atmospheric pressure conditions. Reactions were undertaken with various particle size ranges from 50 to 512.5 μm, and reaction time from 30 to 70 min for reactions of polyesters. Low molecular weight product of polyester was obtained during this process. In the next stage, hydroxylamine hydrochloride (HAHC), cyclohexylamine (CHA), and potasium hydroxide (KOH) solution were introduced to convert low molecular weight product of polyester into terephthalohydroxamic acid (TPHA) by introduction of HCl (Hydrochloric Acid) as per stoichiometric requirement. TPHA can be used as an agrochemical (insecticide) with appreciable efficiency. To increase the polyester conversion rate, external catalyst (0.003 mol lead acetate) was introduced during the reaction. The product was deposited on the surface of unreacted polyester, which was removed from the surface by introducing dimethyl sulfoxide (DMSO). To accelerate the reaction rate, DMSO, CHA, and THF were introduced during the reaction, which has an industrial significance. Depolymerization of polyester was proportional to the reaction time. Depolymerization of polyester was inversely proportional to the particle size of polyester. Analyses of value‐added product (TPHA) and byproducts [EG and BD (1,4‐butanediol)] as well as polyesters were undertaken. A kinetic model is developed, and experimental data simulated with it, which was consistent with the model. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2504–2510, 2006 相似文献
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淀粉接枝丙烯酰胺的合成及其絮凝性能的研究 总被引:3,自引:0,他引:3
以玉米淀粉(St)和丙烯酰胺(AM)单体为原料,采用过硫酸钾引发剂合成了淀粉接枝丙烯酰胺共聚物(St-g-AM)。用红外光谱对接枝共聚物进行了结构表征,用粘度法测定了分子量。讨论了聚合反应的各个因素对接枝共聚反应的影响,考察了接枝共聚物的絮凝性能。结果表明,以接枝效率为考察目标,其最佳的合成工艺为:引发剂的浓度为0.07 g/100 mL,淀粉与丙烯酰胺的质量比为1∶2.2,反应温度为65℃,反应时间3 h。淀粉接枝丙烯酰胺共聚物比430万分子量的聚丙烯酰胺(PAM)对高岭土水样的絮凝性能更好,当接枝共聚物的投加量为6 mg/L时,对高岭土水样的浊度去除率达到81.77%。最佳条件所合成出的淀粉接枝丙烯酰胺的分子量为75万。 相似文献
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Madolyn Babcock David E. Terry Albert J. Milun 《Journal of the American Oil Chemists' Society》1959,36(3):93-94
Summary Commercial production of high molecular weight quaternary ammonium chlorides has necessitated methods for their analysis.
Available methods were found to be lacking in completeness. A successful scheme of analysis was worked out for determining
quaternary ammonium chloride, amine hydrochloride (or free alkali), amine, and sodium chloride. The analytical procedures
as described are straightforward and suitable for routine product and process control.
Paper No. 129, Journal Series, General Mills Inc., Research Department. 相似文献
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魔芋葡甘低聚糖醛酸双酯钠的合成 总被引:6,自引:0,他引:6
以固相多酶系统RT - 4酶解魔芋精粉制得的超滤低聚魔芋葡甘聚糖 (KGM) ,经酸性条件下氧化成低聚KGM醛酸。通过正交实验优化出双酯化条件 :羟丙基化 :m(低聚KGM醛酸 )∶m(环氧丙烷 ) =1 0 0∶1 2 5 ;硫酸酯化 :m(低聚KGM醛酸羟丙酯 )∶m(氯磺酸 ) =1 0∶2 5 ,分别恒温 30℃、6 8℃ ,搅拌反应 3h ,产品低聚KGM醛酸双酯钠对低聚KGM醛酸收率 76 4 % ,相对分子质量 2 0 0 0~ 4 0 0 0 ,结构经IR、1HNMR分析 ,按低分子肝素质量标准药检及药理实验 ,确证是一种新型类肝素药物。 相似文献
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