氯化聚乙烯接枝水溶性单体共聚物的双亲性

以疏水性弹性体氯化聚乙烯(CPE)接枝水溶性单体(丙烯酸AA,丙烯酰胺AM)合成双亲性接枝聚合物(CPE-g-AA,CPE-g-AM)。考察了接枝物的吸水率及亲水/亲油性能。研究发现,双亲性接枝聚合物吸水性能与接枝单体类型及其接枝率有关,接枝物在油/水混合液中的分散状况及吸水/油性能与接枝物的接枝率及所吸有机溶剂溶度参数(δ)有关,随极性单体接枝链含量增大,双亲性接枝物吸水性增强而吸油性降低。     

CPE-g-PEG在CPE/P(AA-AM)吸水膨胀弹性体中的增容作用

选择自制的吸水树脂丙烯酸/丙烯酰胺共聚物(P(AA-AM))与氯化聚乙烯(CPE)为共混原料,以CPE-g-PEG两亲性接枝共聚物为增容剂,机械共混制备了增容型吸水膨胀弹性体(WSE).对共混物的亚微形态、吸水膨胀特性以及力学性能进行了研究.TEM结果表明简单共混时,CPE/P(AA-AM)共混物试样的相容性差.添加CPE-g-PEG后CPE与P(AA-AM)相间有一定程度的连接.接枝物的加入,改善了共混试样的重复使用情况,降低了其质量损失率,提高了WSE的稳定性,改善了试样的力学性能,接枝物加入量为6份时,拉伸强度最大.     

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。     

CPE/P(AA-AM-HMA)吸水膨胀弹性体的研究

采用机械共混将氯化聚乙烯(CPE)与自制的吸水树脂丙烯酸-丙烯酰胺-甲基丙烯酸羟乙酯共聚物[P(AA-AM-HMA)]共混，并且以合成的两亲聚合物为共混试样的增容剂实施增容，讨论了吸水树脂以及增容荆对共混试样的力学性能和溶胀性能的影响。结果表明简单共混时随吸水树脂量增大。共混试样的拉伸强度降低，其吸水率增大。CPE-g-PEG的加入改善了试样的力学性能，与氯化聚乙烯／丙烯酸-丙烯酰胺共聚物共混体系相比，CPE／丙烯酸-丙烯酰胺．羟甲基丙烯酸共聚物试样吸水慢．平衡吸水率较大，质量损失率较小，而且受盐的影响较小。     

聚乙烯熔融挤出接枝马来酸酐的研究

通过低密度聚乙烯熔融挤出接枝MAH(马来酸酐)研究了单体及复配单体、引发剂及复配引发剂对LDPE接枝的影响,并用红外光谱法证实了接枝反应。研究表明:复配单体和复配引发剂用量对接枝率有较大影响,AA(丙烯酸)的加入提高了接枝率,DCP/BPO为3/1时接枝率最高。在聚乙烯防雾膜中加入PE g MAH接枝共聚物可提高膜的防雾性。     

丙烯酸-丙烯酰胺共聚物吸水树脂的制备

采用溶液聚合法,以丙烯酸(AA)和丙烯酰胺(AM)为单体,N,N’-亚甲双丙烯酰胺(NMBA)为交联剂,过硫酸铵为引发剂,制备了丙烯酸-丙烯酰胺共聚物吸水树脂,探讨了单体配比(mAA/mAM)、交联剂和引发剂用量对树脂吸水率的影响。结果表明:在65℃时,丙烯酸-丙烯酰胺共聚物吸水树脂的最佳制备条件为:丙烯酸和丙烯酰胺质量比为4:1,交联剂和引发剂用量分别为聚合单体(丙烯酸和丙烯酰胺)总质量的0.02%和0.4%。     

CPE-g-(AM-co-MAH)增容氯化聚乙烯吸水膨胀弹性体的研究

采用机械共混法将氯化聚乙烯(CPE)与自制吸水树脂丙烯酸钠-丙烯酰胺-甲基丙烯酸羟乙酯三元共聚物P(NaAA-AM-HMA)共混合成吸水膨胀弹性体,讨论了吸水树脂用量、增容剂CPE-g-(AM-co-MAH)用量对吸水膨胀弹性体吸水性能、力学性能的影响。结果表明,未添加增容剂的共混物随吸水树脂量增大,吸水率增大,但是力学性能降低。将增容剂添加到共混试样中,改善了CPE与吸水树脂P(NaAA-AM-HMA)的相容性,提高了体系的力学性能和吸水性能,以加入3Phr的CPE-g-(AM-co-MAH)的增容效果最为明显。     

PVC氯化原位接枝丙烯酸的合成和表征

研究了以氯气作为引发剂对PVC进行氯化原位接枝丙烯酸(AA)的过程,对分离纯化后的接枝物进行了表征和分析;同时还测定了接枝共聚物中丙烯酸的接枝率,考察了反应温度、反应时间、单体用量对产物接枝率的影响.结果表明,反应过程生成了聚氯乙烯接枝丙烯酸的共聚物(CPVC-g-AA);当反应温度为120℃,AA为10份,反应时间为3 h时,丙烯酸的最大接枝率达1.21%.     

丙烯酰胺/甲基丙烯酸丁酯改性纤维素的研究

以纤维素为基体,丙烯酰胺(AM)、甲基丙烯酸丁酯(BMA)为接枝单体,过硫酸钾为引发剂,N,N'-亚甲基双丙烯酰胺为交联剂,聚乙烯吡咯烷酮为分散剂,通过悬浮接枝聚合法制备出了纤维素基吸水吸油材料;考察了单体用量、引发剂用量、反应时间、反应温度及交联剂用量等因素对接枝聚合物的吸水、吸油性能的影响。结果表明:在单体与纤维素的质量比为3.0∶1.0,AM∶BMA的质量比为2.0∶1.0,相对于单体,引发剂质量分数为6.0%,交联剂质量分数为0.5%,分散剂质量分数为0.5%,反应温度为70℃,反应时间为4 h的条件下,得到纤维素-AM-BMA接枝共聚物,其吸油倍率为11.55 g/g,吸水倍率为23.51 g/g,聚合度为534.6。     

两亲性接枝物CPE-g-AM-MAH的合成条件研究

采用悬浮溶胀法将丙烯酰胺(AM)、马来酸酐(MAH)与氯化聚乙烯(CPE)进行接枝反应,制备得到了两亲性共聚物(CPE-g-AM-MAH),用红外光谱对接枝物结构进行了表征,利用正交试验法讨论了氯化聚乙烯、马来酸酐、AM/MAH比率、引发剂对接枝率和接枝效率的影响.结果表明:各影响因素对接枝率的影响顺序为AM>CPE>...     

Preparation and properties of water‐swellable elastomer

A series of water‐swellable elastomers were prepared by blending chlorinated polyethylene (CPE) with poly(acrylic acid–acrylic amide) [P(AA–AM)]. The effect of component on its water‐absorbent properties such as degree of swelling, swelling ratio, and weight loss ratio was discussed. Mechanical behavior of blends was also investigated. The results indicate that swelling rate of CPE/P(AA–AM) was very quick; the blend reached its equilibrium state in only 30 min. The equilibrium swelling ratio increased with increasing amounts of water‐absorbent resin, the greater the amount of P(AA–AM), the higher the swelling degree. The effect of temperature on swelling ratio was very interesting, below 30°C, with an increase of temperature, the swelling ratio of blend increased, but above 30°C, with an increase of temperature, the swelling ratio decreased, indicating that this is a temperature‐sensitive water‐swellable elastomer. The effect of pH of solutions on the swelling behavior showed that water absorption of blends was heavily influenced by pH. The effect of different metal ions on the swelling behavior were also studied and the results showed that the absorption of blends was decreased dramatically with increasing the charge number of the cation, but was not influenced by radius and valence state of the anion. Owing to the compatibility of the amphiphilic graft copolymer (CPE‐g‐PEG), the equilibrium swelling ratio of the blends increased and the weight loss ratio decreased. Adding CPE‐g‐PEG can improve the mechanical behavior of blends. But too much grafted copolymer can worsen the tensile strength of blends. Tensile strength of blends decreased with an increase in P(AA‐AM). After absorbing water, the material's strength is greater than in the dry state. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1719–1723, 2004     

聚(丙烯酸-丙烯酰胺)接枝辛基酚聚氧乙烯醚丙烯酸酯两亲性共聚物的合成及表征

以辛基酚聚氧乙烯醚丙烯酸酯(C8PhEO10Ac)为大分子单体,丙烯酸(AA)、丙烯酰胺(AM)为共聚单体,采用大分子单体接枝共聚法,制备了一种两亲性接枝共聚物(AA-AM-g-C8PhEO10Ac),用静态光散射(SLS)与GPC联用技术测得接枝共聚物的分子量为9.51×105,用FTIR、1H NMR和TG/DTA等手段对共聚物的结构及性能进行了表征。采用透射电子显微镜(TEM)对聚合物在水溶液中的自组装行为进行了初步研究。结果表明,AA-AM-g-C8PhEO10Ac在水溶液中自组装,形成球型胶束,随着浓度增大,趋向于形成更大的自组装体。     

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.     

响应曲面法优化XG/AM接枝共聚物的合成工艺

为优化黄原胶(XG)与丙烯酰胺(AM)接枝共聚物(XG-g-AM)的合成工艺,以产品接枝率、接枝效率的回归综合得分为指标,采用响应曲面(RS)法分析了m(AM)∶m(XG)比例、XG浓度和辐射总剂量(60Co-γ为辐射源)对产物接枝参数的影响,并建立了相应的预测模型;同时利用元素分析、红外光谱(FT-IR)和X射线衍射(XRD)法对接枝产物的结构进行了表征。结果表明:AM已成功接枝在XG上,并且当m(AM)∶m(XG)=2.9∶1、XG浓度为9.8 g/L和辐射总剂量为5.9 kGy时,相应产品的接枝率、接枝效率回归综合得分的预测值(19.95)最大;验证了最佳工艺条件下制备的产品接枝率为130.2%,平均接枝效率为80.4%,综合得分为19.78,试验值与预测值吻合较好,说明该模型可以较好地反映综合得分与各影响因素之间的关系。     

瓜尔胶/丙烯酰胺的反相乳液接枝共聚

以硝酸铈铵/硝酸为引发剂,在反相乳液中引发瓜尔胶/丙烯酰胺的接枝共聚反应。考察了m(丙烯酰胺AM)∶m(瓜尔胶GG)、引发剂浓度、反应温度和反应时间对接枝聚合的影响。结果表明,当m(AM)∶m(GG)=3∶2,引发剂浓度为4 mmol/L,反应时间为4 h,反应温度为45℃时,接枝共聚反应的接枝率和单体转化率分别为147.05%和87.7%。接枝共聚物的最大相对分子质量(简称分子量,下同)可达到1.73×106。红外光谱(IR)分析证明了AM确实接枝到GG分子链上,热重分析(TGA)显示接枝的AM单体并未影响GG的热稳定性。     

高吸水树脂的共聚组成与微球性能

采用反相悬浮聚合法,制备了部分中和的丙烯酸(AA)与丙烯酰胺(AM)共聚的球状高吸水树脂。研究了不同单体组成对微球的共聚组成、吸液性能和颗粒形态的影响。结果表明,在碱性水介质中,AM是竟聚率较小的单体,间歇共聚合的共聚物微球的组成是不均一的。微球的吸水能力随AM含量的增大而降低,当AM在共聚单体中质量分数为30%时,树脂对盐水的吸收能力具有协同效应,表明非离子型单体的耐盐性较好。显微镜观察表明,部分中和的聚丙烯酸微球为规整的球形,而共聚物微球则为不规整的球形。     

新型黄原胶基高吸水性树脂的合成

在水溶性引发剂过硫酸钾的引发下,使丙烯酸（AA）在黄原胶（XG）分子链上接枝聚合,并加入N,N′-亚甲基双丙烯酰胺进行一定程度的交联,制备高吸水性树脂。研究了反应条件对产品吸水率的影响,利用傅里叶红外光谱、X射线衍射、偏光显微镜对接枝共聚物进行表征。实验结果表明：最佳合成条件AA与XG质量比m(AA) ∶m(XG)=6∶1,交联剂、引发剂与黄原胶的质量比分别为0.01和0.003,丙烯酸的中和度为70%,反应温度为60 ℃,反应时间为4 h。最佳合成条件下制备的树脂最大吸水倍数854 g/g,吸生理盐水倍数156 g/g。     

Grafting onto polyformaldehyde fibers

Acrylic acid (AA), acrylonitrile (AN), and acrylamide (AM) were grafted onto polyformaldehyde (PF) fibers employing γ-ray irradiation as well as benzoyl peroxide initiation. The nature of the graft copolymer obtained from a given monomer was dependent on the type of method used for the grafting reactions. This was reflected in the various characteristics of the grafted PF fibers such as moisture regain and dyeability to disperse, direct, basic, and acid dyes. The extent of grafting was dependent on time, concentration of the initiator, concentration of monomer, and irradiation dose. The grafting reaction with all the three monomers and both methods of grafting studied followed first-order kinetics. The rate constant values for grafting with AA, AN, and AM were 0.493, 0.576, and 0.420 hr^?1, respectively for the irradiation method and 0.385, 0.385, and 0.346 hr^?1, respectively, for the benzoyl peroxide initiation technique. The increase in the moisture regain was directly proportional to the amount of graft in the fiber. Acrylic acid grafted PF fibers were rendered hydrophilic to the highest extent (7.9% M.R. for 42% graft), while AM-grafted fibers were rendered so to the lowest extent (7.23% M.R. for 76.5% graft). Considerable improvement in dyeability of PF fibers was observed as a result of grafting. In general, dyeability was proportional to the amount of graft introduced in the fibers. The AA-grafted PF fibers gave a six-to sevenfold increase in disperse dye content when the irradiation method was followed and a four-to fivefold improvement when the chemical method was used during the grafting reaction. The AA-grafted and AM-grafted PF fibers show considerable affinity toward direct cotton dyes. The two substrates could also be dyed with fiber-reactive dyes in deep fast shades, the AM-grafted PF fibers giving deeper shades as a result of higher reactivity imparted to the substrate by the NH₂ group of the graft copolymer. The AA- and AN-grafted PF fibers could be dyed in intense deep shades with cationic dyes. Similarly, AM-grafted substrates gave bright deep shades with acid dyes. Infrared studies, used to analyze the grafted PF fibers, indicated the presence of ? COOH, ? CN, and ? NH₂ groups introduced in the fiber structure as a result of grafting with AA, AN, and AM.