双螺杆冻胶纺丝法制备有机液体吸附功能纤维及其性能研究

在聚合釜中合成了BMA/HEMA二元共聚树脂,利用双螺杆纺丝机、采用冻胶纺丝技术制备了有机液体吸附功能纤维,研究了单体投料比中HEMA质量分数对纤维各种溶胀行为的影响,利用动态热机械分析仪(DMA)对纤维的动态力学性能进行了研究,同时利用环境扫描电子显微镜(SEM)观察了纤维的表面和断面形貌.结果表明,HEMA引入大分子后,所得纤维对有机液体甲苯、三氯乙烯具有吸附功能,且吸附过程符合sigmoidal模型中的Hill方程;随HEMA质量分数的增加,纤维对甲苯和三氯乙烯的饱和吸附量增大,对甲苯和三氯乙烯的最大吸附量分别可达10g/g和21g/g;随HEMA质量分数的增加,纤维剩余率增加的同时,使纤维对甲苯和三氯乙烯的握持能力增强;HEMA质量分数对纤维动态力学性能有突出影响,特别是链段运动受其影响更为明显;HEMA质量分数对纤维表面和断面形貌均有显著影响,特别是当HEMA质量分数为15wt%时,所得纤维表面出现了许多空洞,其断面存在许多尺寸不均的空洞.     

PLMA/PU共混纤维的制备与吸附性能

以聚乙烯醇(PVA)为分散剂,过氧化苯甲酰(BPO)为引发剂,采用水相悬浮聚合法合成了聚甲基丙烯酸十二酯(PLMA),将其与聚氨酯(PU)共混、造粒、熔融纺丝制得PLMA/PU共混纤维.通过傅里叶变换红外光谱仪(FTIR)、扫描电子显微镜(SEM)、单纤维强力仪及光学接触角测量仪等分析了纤维的结构与性能,同时研究了纤维对有机液体的吸附性能及循环使用性能等.研究结果表明,纤维具有良好的疏水亲油性,吸附后,纤维形态明显胀大;纤维对油性低分子有机物具有良好的吸附性能,其中对甲苯、三氯乙烯、柴油、煤油和含有原油(质量分数为10%)的甲苯溶液最大吸附率分别为4.86,8.1,2.42,2.04和3 g/g,吸附油品后的纤维经脱附可多次循环使用;PLMA对纤维吸附有机液体起决定作用,而PU的存在对纤维吸油时保持形态和纺丝成形起到重要作用.     

甲基丙烯酸二甲胺乙酯对光固化阴极电泳漆性能的影响

通过自由基共聚合得到丙烯酸树脂,然后用甲基丙烯酸异氰酸乙酯(MOI)对其改性,合成了既带有N,N-二甲胺基,又带有乙烯基的紫外光固化阴极电泳漆基体树脂。研究了甲基丙烯酸二甲胺乙酯(DMAE-MA)用量对改性丙烯酸树脂水分散体和漆膜性能的影响规律。结果表明,树脂分子链上引入DMAEMA后,其水分散性有较大改善,随DMAEMA用量增加,水分散体的粒径减小、粘度略有增加、稳定性增强,电泳沉积量和漆膜厚度增加,电泳沉积漆膜的初期含水率增加。综合考虑水分散体和漆膜的性能,丙烯酸树脂中DMAEMA质量分数以0．144左右为宜。     

不同交联剂对甲基丙烯酸-β-羟乙酯/E-51双甲基丙烯酸酯聚合物水凝胶性能的影响

以水溶性单体甲基丙烯酸-β-羟乙酯(HEMA)与大分子交联剂E-51双甲基丙烯酸酯(E-51-DMA)(质量比HEMA/E-51-DMA=90/10)为主要原料,分别引入了5种小分子交联剂:N,N′-亚甲基双丙烯酰胺(MBA)、二乙烯基苯(DVB)、双甲基丙烯酸乙二醇酯(EDMA)、1,1,1-三(丙烯酰氧甲基)丙烷(TAP)和2,2,2-三(丙烯酰氧甲基)乙醇(TAE),采用本体聚合方法合成了5个系列的聚合物水凝胶.研究了小分子交联剂的类型及用量对水凝胶溶胀性能、杨氏模量以及有效交联密度ve和聚合物-水相互作用参数χ的影响,并比较了不同交联剂的交联效率.结果表明,随着小分子交联剂用量的增大,水凝胶平衡含水量EWC逐渐降低,聚合物体积分数2逐渐增大,反映聚合物网络结构的有效交联密度ve以及热力学参数聚合物-水相互作用参数χ值也随之增大.通过理论交联密度和有效交联密度的线性拟合,得到所选用的5种小分子交联剂在E-51-DMA10/HEMA90水凝胶体系中的交联效率,其顺序为DVB>EDMA>TAE>MBA≈TAP.     

聚甲基丙烯酸羟乙酯树脂对胆红素的吸附研究

本文通过水相悬浮聚合制备了大孔交联聚甲基丙烯酸羟乙酯（PHEMA）树脂，研究了PHEMA树脂以及用乙醇胺功能基化后的PHEMA树脂对胆红素的吸附性能。结果表明，PHEMA树脂对胆红素的吸附性能受树脂孔结构，吸附温度，离子强度以及溶液中白蛋白的影响。该类吸附剂对胆红素有良好的吸附性能，其中用乙醇胺功能基化的树脂表现出更好的吸附能力。     

溶剂浸渍树脂孔结构的研究

用萃取剂N_(235)浸渍大孔苯乙烯—二乙烯苯(MSD)树脂制得了溶剂浸渍树脂。用压汞仪测定了溶剂浸渍树脂的孔体积、孔表面积和孔径等,用扫描电镜观察了溶剂浸渍树脂的形貌。MSD树脂对N_(235)吸附率随该树脂的交联度和混合致孔剂用量增加而增加。由于N_(235)分布于MSD树脂孔表面,浸渍树脂的孔体积、孔表面和孔径比MSD树脂显著下降。在孔径1～100nm孔表面吸附N_(235)量最大。低交联度MSD树脂对N_(235)吸附量低,且分布不均匀。     

三聚硫氰酸交联聚氯乙烯树脂的合成及其对Cu~(2+)的吸附性能

以三聚硫氰酸为原料,邻苯二甲酸二辛酯(DOP)为增塑剂,聚氯乙烯为大分子骨架,在MgO的存在下,合成得到了三聚硫氰酸交联聚氯乙烯树脂.对交联树脂吸附重金属离子的性能研究表明,合成树脂对Cu2+的吸附容量及选择性最大,在实验条件下吸附量达到1.056mmol/g;对其他金属离子吸附量很小,甚至不吸附.     

3,5-二硝基苯甲酸酯基改性的HEMA/NVP交联微球对肌酐的吸附特性与吸附机理

制备了平均粒径为180μm的甲基丙烯酸β-羟乙酯(HEMA)与N-乙烯基吡咯烷酮(NVP)交联共聚物微球(HEMA/NVP),使用3,5-二硝基苯甲酰氯(DNBC)对其进行了化学改性,制得了表面键合有大量3,5-二硝基苯甲酸酯基(DNBZ)的功能微球DNBZ-HEMA/NVP;采用红外光谱(FTIR)与化学分析法对其化学结构及组成进行了表征;重点研究了功能微球DNBZ-HEMA/NVP对肌酐的吸附特性与吸附机理.静态吸附实验表明,DNBZ-HEMA/NVP对肌酐具有强的吸附作用,交联微球HEMA/NVP经DNBC化学改性后,对肌酐的吸附容量提高了20倍;DNBZ-HEMA/NVP对肌酐的吸附性能受介质pH值及盐度的影响很大;当pH值较小或较大时,吸附容量都较低,pH=8.5时,吸附容量最大;介质的盐度越大,吸附容量越小.研究结果表明,DNBZ-HEMA/NVP对肌酐的吸附属化学吸附,而且是静电相互作用驱动下的化学吸附.     

大孔交联聚乙烯咪唑啉树脂的合成及性能研究

本文分别以二乙烯苯和双甲基丙烯酸乙二醇酯为交联剂,合成了大孔交联聚丙烯腈吸附树脂,测定了两系列树脂的孔和表面性能。同时以上述材料为母体,通过与乙二胺反应将腈基进行化学转化,制得大孔交联聚乙烯咪唑啉树脂,并探讨了该树脂在碱性介质中(pH10)对Au~+的吸附性能。     

甲基丙烯酸烷基酯为疏水成分的溶剂改性pH-敏感凝胶的溶胀行为

以不同酯烷基链长的甲基丙烯酸烷基酯为疏水成分，甲基丙烯酸二乙氨基乙酯(DEA)为可离子化单体，及以二甲基丙烯酸乙二醇酯(EGDM)或二乙烯苯(DVB)为交联剂，合成了数个系列甲苯改性的不同交联度的疏水阳离子凝胶，研究了这些凝胶以pH-敏感溶胀为主的容胀行为．发现以甲基丙烯酸正丁酶(BMA)，EGDM及DEA合成的改性凝胶，与以苯乙烯(St)，DVB及DEA合成的溶剂改性凝胶具有十分相似的平衡溶胀和动力学溶胀性质．研究结果为增加疏水阳离子凝胶的载药种类，拓宽由pH改变而触发释药的控释体系的应用范围提供了新的途径．     

Semibatch Emulsifier-free Emulsion Copolymerization of Methyl Methacrylate and n-Butyl Acrylate in the Presence of 2-Hydroxyethyl Methacrylate

ThemethodsofimProvingthestabilityofemulsifier-freeemulsionpolymerizationhavebeenreportedinliteraturet(a)choosingionizableinitiators,suchaspotassiumpersulfate'andazo-bis(isobutyramidinehydrochloride)';(b)copolymerizationwithhydrophiliccomonomers,whichinvolvestheionictypesuchascarboxylicmonomers',sulfoderivativesofvinylmonomers',andthenonionictypesuchasglycidylmethacrylate';(c)copolymerizationwithsurface-activemonomers,suchassulfodecylslyrylether';(d)addingorganicsolventstothesystem,suchasmethano…     

Low- and high-conversion studies of the free radical copolymerization of 2-hydroxyethyl methacrylate with styrene in N,N′-dimethylformamide solution

2-Hydroxyethyl methacrylate (HEMA) and styrene (S) have been copolymerized in a 3 mol · L⁻¹N,N′-dimethylformamide (DMF) solution using 2,2′azobis (isobutyronitrile) (AIBN) as an initiator over a wide composition and conversion range. From low-conversion experiments and ¹H-NMR analysis, the monomer reactivity ratios were determined according to the Mayo–Lewis terminal model. The comparison of the obtained results with those previously reported for copolymerization in bulk and in toluene reveals a relatively small but noticeable solvent effect that can be qualitatively explained by the bootstrap model. Cumulative copolymer composition as a function of conversion is satisfactorily described by the integrated Mayo–Lewis equation; overall copolymerization rate increases with increasing the HEMA/S ratio, and individual monomer conversion is closely related to the monomer molar fraction in the feed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2941–2948, 1999     

聚氯乙烯-g-聚甲基丙烯酸-2-羟乙酯共聚物的合成和表征

聚氯乙烯 (ＰＶＣ)是常用医用高分子材料之一 ,可以制作储血袋、导液管、人工尿道等 .ＰＶＣ亲水性差 ,影响其生物相容性 .采用亲水性单体与ＰＶＣ接枝共聚是提高ＰＶＣ亲水性的重要方法[1] .Ｋｒｉｓｈｎａｎ等[2 ] 对Ｃｏ60 辐照下ＰＶＣ接枝Ｎ 乙烯基吡咯烷酮进行了研究 .Ｓｉｎｇｈ等[3～ 5] 采用辐照引发甲基丙烯酸在ＰＶＣ薄膜的接枝反应 ,对接枝动力学、接枝后薄膜表面形态、溶胀和抗凝血性等进行了研究 .Ｇｏｌｄｂｅｒｇ等[6] 采用辐照引发甲基丙烯酸2 羟乙酯 (ＨＥＭＡ)在ＰＶＣ薄膜上的接枝 .Ｌｅｅ等[7]采用溶液接枝共聚制备了…     

Effect of Toluene on the Kinetics of Ce(IV)-Ion-Initiated Grafting of Methyl Methacrylate onto Chemically Modified Jute Fibers

A study of the graft copolymerization of methyl methacrylate onto jute fiber using Ce(IV) and toluene has been carried out. The effects of concentration of monomer, Ce(IV), and toluene on graft yield have been studied. The effects of time, temperature, acid, amount of jute fiber, and some inorganic salts and organic solvents on graft yield have also been investigated. The investigation includes characterization of the grafted fiber by infrared and thermo-gravimetric studies. Grafting improves the thermal stability of jute fibers. More than 200% graft yield was achieved in the present investigation.     

Ambient Temperature Photocopolymerization of Tetrahydrofurfuryl Methacrylate and Isobornyl Methacrylate: Reactivity Ratios and Thermal Studies

Photocopolymerization of heterocyclic monomer namely, tetrahydrofurfuryl methacrylate with bulky bicyclic monomer, isobornyl methacrylate with different feed ratios was carried out in bulk with low concentration of an α-hydroxyl ketone based photoinitiator. The ambient temperature photocopolymerization was carried out by using a UV-Visible lamp with fixed low intensity of 0.4 mW cm^?2 for a period of 6 min. The residual monomer remained in the polymerization process were determined by using gas chromatography. The reactivity ratio values for the two monomers were calculated from the copolymer composition data by using Fineman-Ross, Kelen-Tudos, Extended Kelen-Tudos and Mao-Huglin methods. Individually, as well as the average of all the methods revealed that the monomer reactivity ratios of tetrahydrofurfuryl methacrylate were higher than isobornyl methacrylate. The dyad sequence distribution and dyad sequence lengths were calculated using the Igarashi and Pyun method and the sequence length distribution for tetrahydrofurfuryl methacrylate was observed to be higher with an increase in its feed content. This supports the reactivity ratio studies that a higher monomer reactivity ratio value for tetrahydrofurfuryl methacrylate was observed as compared to its comonomer. The thermal studies showed that the glass transition temperatures of the copolymers increased with an increase in isobornyl methacrylate content.     

Graft Copolymerization of Monomer Mixtures Acrylonitrile/Ethyl Acrylate and Acrylonitrile/Methyl Methacrylate on Carboxymethyl Cellulose

Abstract

Graft copolymerizations of acrylonitrile/ethyl methacrylate and acrylonitrile/methyl methacrylate monomer mixtures on carboxy methyl cellulose (d.s. 0.4–0.5) were studied in aqueous medium at 30°C using ceric ion as initiator. The amounts of the polymer grafted were measured as a function of the mole fraction of acrylonitrite in the feed. The compositions of the copolymer samples were obtained from their nitrogen contents. It was found that the presence of acrylonitilte in the polymerization system was associated with reductions (of up to 80%) in the amounts of polymer grafted; and that disproportionately low amounts of acrylonitrile monomeric units were incorporated into the graft copolymer even at relatively high acrylonitrile content of the feed.     

Novel hydrogel membrane based on copoly(hydroxyethyl methacrylate/p-vinylbenzyl-poly(ethylene oxide)) for biomedical applications: properties and drug release characteristics

The aim of this study was to synthesize and characterize a novel biocompatible polymeric membrane system and demonstrate its potential use in various biomedical applications. Synthetic hydrogels based on poly(hydroxyethyl methacrylate), poly(HEMA), have been widely studied and used in biomedical fields. A novel copolymer hydrogel was prepared in the membrane form using 2-hydroxyethyl methacrylate monomer (HEMA) and a macromonomer p-vinylbenzyl-poly(ethylene oxide) (V-PEO) via photoinitiated polymerization. A series of poly(HEMA/V-PEO) copolymer membranes with different compositions was prepared. The membranes were characterized using infrared, thermal and SEM analysis. The thermal stabilities of the copolymer membranes were found to be lowered by an increase in the ratio of macromonomer (V-PEO) in the membrane structure. Because of the incorporation of PEO segments, the copolymers exhibited significantly higher hydrophilic surface properties than pure poly(HEMA), as demonstrated by contact angle measurements. Equilibrium swelling studies were conducted to investigate the swelling behavior of the membranes. The equilibrium water uptake was reached in about 4 h. Moreover, the blood protein adsorption and platelet adhesion were significantly reduced on the surface of the PEO containing copolymer membranes compared to control pure poly(HEMA). Drug release experiments were performed in a continuous release system using model drug (vancomycin) loaded copoly(HEMA/V-PEO) membranes. A specific poly(HEMA/V-PEO) membrane formulation possessing the highest PEO content (with a HEMA:V-PEO (mmol:mmol) feed ratio of 112:1 and loaded with 40 mg antibiotic/g polymer) released about 81% of the total loaded drug in 24 h at pH 7.4. This membrane composition provided the best results and can be considered as a potential candidate for a transdermal antibiotic carrier and various biomedical and biotechnological applications.     

Copolymerization of Chloroprene with Methyl Methacrylate by the EtnAICI3.n (n=1, 1.5, 2)-Vanadium Compound System

Abstract

The copolymerization of chloroprene with methyl methacrylate was studied in the presence of Et_n A1C1_3-n (n=1, 1.5, 2)-vanadium compounds. Monomer reactivity ratios in various catalyst concentrations were compared with that of a usual radical initiator. The apparent monomer reactivity ratio changed with the concentration of alkylaluminum halide. In this polymerization, alternating copolymer could not be prepared by the ordinary catalyst concentration by which the alternating copolymerization of chloroprene with acrylonitrile was carried out. The addition of more than 10 mole % of the alkylaluminum halide based on two monomers was required to prepare the copolymer which had equimolar composition irrespective of the feed monomer ratio.

The configuration in the repeating unit of the copolymer was discussed by comparison with the NMR and IR spectra of the radical copolymer and the cyclic Diels-Alder adduct of chloroprene-methyl methacrylate. The high alternating tendency was clarified by ozonolysis of the copolymer which was prepared under the conditions which produced equimolar copolymer in various feed monomer ratios. The chloroprene unit of the copolymer was present in the 1, 4-trans structure in the copolymer prepared by the Et_n A1C1_3-n -vanadium compound system.     

Analysis for the Reaction of Hydroxyethyl Methacrylate/Benzoyl Peroxide/Polymethacrylate Through DSC and Viscosity Changing and Their Resultants as Oil Absorbent

Polymethacrylate was firstly synthesized via suspension polymerization of the monomers including butyl methacrylate (BMA) and hydroxyethyl methacrylate (HEMA) using benzoyl peroxide (BPO) as initiator. Then a mixture was prepared by mixing the synthesized polymethacrylate with the solution of HEMA and BPO and preserved in a sealed container for 24 h. Thereafter, we employed a differential scanning calorimeter (DSC) to monitor the reaction process of HEMA involved in the mixture at a constant heating rate. The viscosity changing with time for the above mixture was also measured by a rotating viscometer at 85°C with N, N-dimethylformamide (DMF) as diluting agent. Finally, the results of DSC test and viscosity test were analyzed for revealing the reaction mechanism of HEMA involved in the above mixture. Based on this analysis, we chose suitable technology parameters for the above-prepared mixture's reactive extrusion. During the reactive extrusion, the polymerization of HEMA was initiated and the generated PHEMA built an interpenetrating polymer network with the synthesized polymethacrylate by H-bonds to make the extruded resultant applicable for oil absorbent. Then the oil-absorptive capacity of the extruded resultant was characterized through oil absorbency, remaining ratio, and gel fraction, and its internal morphology was observed by polarizing microscope and field emission scanning electron microscopy.