淀粉接枝丙烯酰氧乙基三甲基氯化铵共聚物的合成

以玉米淀粉为原料,在水介质中通过硝酸铈铵引发淀粉与丙烯酰氧乙基三甲基氯化铵(DAC)接枝共聚,制备系列含阳离子季铵基团的淀粉-DAC接枝共聚物,系统考察了反应条件对接枝共聚物接枝率(PG)的影响。结果表明:在本实验体系内可制备较高接枝率的阳离子接枝共聚物。当硝酸铈铵的浓度为1.5×10-2mol/L,m(DAC)∶m(淀粉)=3,反应温度40℃,反应时间4 h时,接枝共聚物的接枝率最高可达118.67%。用FTIR、1HNMR、XRD对接枝共聚物结构进行了表征。     

K_2S_2O_8/NaHSO_3引发丙烯酸甲酯与玉米淀粉接枝共聚的研究

本文研究了K_2S_2O_8/NaHSO_3引发丙烯酸甲脂与玉米淀粉接枝共聚的反应规律,初步探讨了此接枝共聚物的成型加工、力学性能和生物降解等。     

交联玉米淀粉-醋酸乙烯酯接枝共聚乳液的制备及性能

碱性条件下,玉米淀粉经环氧氯丙烷交联处理后,在引发剂存在下,与醋酸乙烯酯进一步接枝共聚制得了交联玉米淀粉-醋酸乙烯酯乳液,经红外光谱确认了共聚物,较好的乳液制备工艺:m(淀粉)∶m(环氧氯丙烷)=25∶1,90°C交联1 h,加入过硫酸铵,按m(醋酸乙烯酯)∶m(淀粉)=3∶1,在70°C接枝共聚3 h。各种淀粉胶液的性能对比结果表明:交联玉米淀粉-醋酸乙烯酯接枝聚合乳液冷热稳定性好,耐水性≥54 h,储存期360 d,剪切强度达9.1 MPa。     

淀粉与丙烯酰胺接枝共聚物的合成及絮凝助留性能

采用乳液聚合技术 ,以水为分散介质 ,十二烷基苯磺酸钠为乳化剂和分散稳定剂 ,用过硫酸钾引发丙烯酰胺 (AM)对淀粉 (St)的接枝共聚。接枝共聚物 (St -PAM)在 16 5 0、16 16和 1416cm-1(聚丙烯酰胺PAM的特征吸收 )处的红外光谱表明 ,在淀粉链上引入了酰胺基。控制接枝共聚条件 ,可使丙烯酰胺的接枝效率 (共聚单体占全部聚合单体的质量分数 )达到 90 .0 % ,共聚物中丙烯酰胺的接枝百分率 (St-PAM中PAM的质量分数 )达到 6 0 .9%。显著地改善了淀粉的糊化特性 ,减弱了直链淀粉的凝沉和胶凝倾向 ,使其在冷水中就具有良好的分散性。研究了淀粉与丙烯酰胺接枝共聚的特点 ,考察了单体用量、反应温度、引发剂等因素对接枝共聚的影响 ,以及接枝共聚物对纸浆的絮凝和助留效果的影响。共聚物中丙烯酰胺的接枝百分率愈高 ,纸浆的絮凝速度和留着率愈大 ,接枝百分率为 6 0 .9%的共聚物可使纸浆的网上留着率提高 12 .3%。     

AMPS/AM/木薯淀粉接枝共聚物制备工艺的研究

研究了2-丙烯酰胺基-2-甲基丙磺酸(AM PS)、丙烯酰胺(AM)与木薯淀粉接枝共聚物的接枝共聚工艺条件。结果表明单体用量、引发剂用量、反应温度和反应时间对单体转化率、接枝率、接枝效率有较大影响,制备的AM PS/AM/木薯淀粉接枝共聚物具有较好的吸水性能。     

淀粉反相乳液法三元接枝共聚改性研究与表征

以丙烯酰胺(AM)和丙烯酸(AA)为接枝单体,采用反相乳液聚合技术对木薯淀粉进行接枝共聚改性,生成淀粉-丙烯酰胺-丙烯酸三元接枝共聚物(St-g-AM/AA)。考察反应温度和时间、引发剂和单体浓度、单体配比等因素对淀粉三元接枝共聚反应过程的影响规律,并通过红外光谱等表征共聚物结构。实验结果显示:引发剂浓度、单体浓度和单体比、反应温度和时间等因素对三元接枝共聚改性反应影响显著;红外光谱和电镜扫描表征证明接枝共聚反应发生在淀粉颗粒表面,经三元接枝共聚反应淀粉已被AM和AA成功改性。     

K2S2O8-Na2S2O3引发淀粉与丙烯酸接枝产物吸水性能的主要影响因素

以玉米淀粉和丙烯酸为主要原料,采用溶液聚合的方法,制备了淀粉与丙烯酸接枝共聚物,用FTIR等方法对共聚产物结构进行了表征。研究了在过硫酸钾-硫代硫酸钠组成的氧化-还原引发体系中,引发剂、交联剂不同浓度及丙烯酸不同中和度等因素对共聚产物吸水性能的影响。实验结果表明采用K2S2O8-Na2S2O3引发体系,通过控制引发剂、交联剂浓度,接枝产物吸去离子水可达920 g/g;采用玉米粉代替玉米淀粉与丙烯酸接枝共聚,产物吸去离子水可达870 g/g;这些实验结果进一步提高了吸水树脂的吸水能力。     

乳液型丙烯酸树脂改性阳离子淀粉增干强剂的制备及性能

淀粉与阳离子醚化剂在碱性介质和氧化剂存在下 ,搅拌加热至 6 5～ 70℃ ,进行氧化降解和阳离子化反应 ,反应时间为 2h。再加入丙烯酸及丙烯酸酯单体于 80～ 85℃进行接枝共聚 ,m (玉米淀粉 )∶m (改性单体 ) =1 0∶0 8时 ,得到的乳液型丙烯酸树脂接枝共聚阳离子淀粉增干强剂的增强效果最好 ,对增加纸张干强度和耐撕裂度有明显效果 ,用量为绝干浆质量的 0 4%～ 0 .5 %时 ,可使纸的干强度增加 15 %以上 ,耐撕裂度提高 8%以上。并用IR、SEM、DSC等手段对这种接枝共聚物的结构与性能进行了表征     

淀粉与二甲基二烯丙基氯化铵的接枝共聚研究

以过硫酸铵一尿素为引发剂,可溶性淀粉为原料,实现了淀粉与DMDAAC、丙烯酰胺的三元接枝共聚,着重考察了单体配比、引发剂浓度、反应温度、反应时间等因素对接枝共聚的影响,得到了该聚合反应的适宜条件:(NH4)2SO8浓度为0.33 mmol/L,淀粉与单体总量的质量比为1:9,AM与DMDAAC摩尔比是12:1,反应温度40℃,反应5 h.接枝率可达89%,并用红外光谱、核磁共振谱图对接枝物进行了结构表征.     

化学引发合成淀粉接枝共聚物的研究进展

淀粉与乙烯基单体接枝共聚是淀粉化学改性的重要方法 ,在利用农产品和开发新型功能材料方面有很好的发展前景。综述了近十年化学引发合成淀粉接枝共聚物的研究进展。     

淀粉基木材胶黏剂的制备与性能

以玉米淀粉为接枝骨架,过硫酸铵为引发剂,与接枝单体乙酸乙烯酯-丙烯酸丁酯进行接枝共聚反应,制取淀粉基木材胶黏剂。对得到的淀粉接枝共聚物进行了表征分析及性能研究。IR谱图表明,样品除了保持淀粉的特征吸收峰外,在1730—1740cm。之间出现了羰基特征吸收峰。X-粉末衍射图表明,样品多为弥散峰,证明淀粉接枝共聚物基本为少量结晶态与无定形态共存的结构。TG、DTA曲线证实了接枝共聚反应的发生,且淀粉接枝共聚物的热稳定性优于纯玉米淀粉。性能测试结果表明,制备的胶黏剂具有较好的高温稳定性、粘接性,各项指标已达到了国家标准HG／T2727—95中聚乙酸乙烯酯木材胶黏剂的性能指标,特别是压缩剪切干强度远远超过了国家标准。     

反相乳液法淀粉丙烯酰胺接枝共聚反应的研究

以木薯淀粉为主要原料,研究了淀粉/丙烯酰胺单体/乳化剂/油/水反相乳液体系的接枝共聚反应规律,考察了反应温度、引发剂和乳化剂浓度、淀粉单体比、油水比等因素对淀粉接枝丙烯酰胺共聚反应过程的影响,并对反应机理进行了探讨.结果显示：在本实验考察范围内引发剂浓度、单体淀粉比、反应温度影响显著;乳化剂用量和油水比对反相乳液体系的形成及稳定有重要的影响;淀粉与亲水性单体丙烯酰胺的接枝共聚反应为淀粉团粒表面控制.     

MMA/BA混合单体固相接枝玉米淀粉共聚反应的研究

对玉米淀粉与甲基丙烯酸甲酯、丙烯酸丁酯的固相接枝共聚反应进行了研究,采用红外光谱表征了淀粉接枝共聚物的结构,讨论了各反应因素对接枝率、接枝效率和单体转化率的影响。最佳工艺条件为:引发剂用量为7 phr水,用量为35 phr,反应温度为60℃,反应时间为50~60 min。     

Swelling and rheology of saponified starch–g–polyacrylonitrile copolymers. Effect of starch granule pretreatment and grafted chain length

A series of well-characterized starch–g–polyacrylonitrile (PAN) graft copolymers was prepared from corn starch which had been heated in water at temperatures up to 94°C to vary the extent of starch granule swelling and disruption. Graft polymerization onto gelatinized starch gave less frequent grafting of higher molecular weight PAN than comparable graft polymerizations onto ungelatinized starch. A graft copolymer was also prepared from gelatinized starch under high dilution conditions to give lower molecular weight grafted PAN and more frequent grafting. Graft copolymers were then saponified with sodium hydroxide to convert nitrile substituents to a mixture of carboxamide and sodium carboxylate. Saponified graft copolymers were only partially water soluble and consisted largely of highly swollen, insoluble gel, which was separated from solubles for the study of physical properties. Saponification mixtures were also dried to yield highly absorbent polymer films. With the exception of the graft copolymer prepared under high dilution conditions, the physical properties of saponified graft copolymers depended on whether or not the granules of starch were gelatinized before graft polymerization. Compared with saponified graft copolymers derived from ungelatinized starch, those prepared from gelatinized starch gave films that absorbed larger amounts of aqueous fluids. Also, the gel fractions from these saponified gelatinized polymers exhibited higher water swelling, lower shear modulus, and a lower reduced viscosity function (η/cQ). The saponified graft copolymer prepared from gelatinized starch under high dilution conditions more closely resembled those prepared from ungelatinized starch, suggesting that molecular weight of grafted PAN and the grafting frequency rather than starch granule pretreatment might be the most important factor which influences properties.     

降解淀粉/DMDAAC-AM接枝共聚物复鞣剂的合成及应用

酶降解淀粉与二甲基二烯丙基氯化铵(DMDAAC)和丙烯酰胺(AM)在引发剂(NH4)2S2O8(APS)作用下进行了接枝共聚合反应,制得阳离子型淀粉复鞣剂。第一步酶降解条件为m(蒸馏水)∶m(淀粉)∶m(α 淀粉酶)=180∶20∶0 2,在60℃降解1h。第二步接枝聚合反应条件为m(DMDAAC)∶m(AM)∶m(APS)=40∶20∶1 5,在75℃保温反应2h。接枝共聚物的接枝率及接枝效率分别为150%和78%,单体转化率及阳离子度分别为98 5%和37%,复鞣革对于染料及加脂剂的吸收率分别为97 3%和96 2%,用红外光谱(FTIR)对复鞣剂的结构进行了表征。     

丙烯腈接枝交联淀粉的制备及应用研究

以玉米交联淀粉为原料,环氧氯丙烷为交联剂,制备了交联接枝玉米淀粉;再以FeSO4-H2O2为引发剂,研究了丙烯腈接枝交联淀粉的制备工艺及其在处理生活污水方面的应用。结果表明,10g玉米交联淀粉、丙烯腈用量10mL、引发剂用量4mL、接枝时间1.5h、反应温度40℃,此条件下接枝率可达83.7%,接枝效率为116.3%,丙烯腈接枝交联淀粉处理过的污水透光率达96.5%。     

Synthesis and Characterization of Starch-Poly(vinyl Acetate) Graft Copolymers and their Saponified Form

A redox initiation system based on potassium persulfate/acetone sodium bisulphite (KPS/ASBS) was developed to initiate the graft copolymerization of vinyl acetate (VAc) monomer onto corn starch in aqueous solution. The grafting reaction was studied with respect to grafting yield (GY), grafting efficiency (GE) and total conversion (TC) and results obtained were compared with those a well-established redox initiation system namely potassium persulfate/sodium bisulphite (KPS/SBS). The effect of reaction variables such as redox initiator concentration, liquor ratio, reaction time and temperature as well as VAc concentration were investigated. The GY, GE and TC increased significantly with increase of the redox initiation concentration up to 8/16 mmol/l irrespective of the initiation system used. Moreover, optimal grafting was obtained at 60 ^○C for KPS/ASBS redox system and 70 ^○C for KPS/SBS redox system. Saponification of poly (vinyl acetate)-starch graft copolymers were effected using NaOH in three different bath media (n-hexane, acetone or methanol) to convert starch-g-poly(vinyl acetate) to starch-g-poly(vinyl alcohol). Higher extent of solubility in hot water of the saponified form was achieved by using a bath containing n-hexane/sodium hydroxide; however, increasing the graft yield higher than 26.3% decreases the solubility. The structures and thermal stability of starch, grafted starch copolymer and saponified grafted starch copolymer were characterized by infrared spectroscopy and thermogravimetric analysis. Moreover, the rheological behavior as well as sizing performance of the saponified grafted starch copolymers were evaluated and compared with the native starch and commercial polyvinyl alcohol.     

羧甲基淀粉接枝共聚物降失水剂研究

以玉米淀粉为原料,对其进行碱化及醚化,将醚化中间体与AM、AA、DMDAAC进行接枝共聚.玉米淀粉羧甲基化的最佳合成条件为：40℃碱化1h,水∶淀粉=1∶1（质量比）,NaOH∶ClCH2 COOH=2.25∶1（摩尔比）,以及醚化时间为3h、温度51℃.CMS与烯类单体接枝共聚的最佳合成条件为：硝酸铈铵∶过硫酸钾=1∶1（质量比）,反应温度55℃,时间4h.接枝共聚产品的降滤失性能有所差异,当各自降滤失性能发挥至极佳时,产品的最佳合成配方也不尽相同.