三油酸甘油酯在共聚物水凝胶膜上的沉积作用

以N-乙烯吡咯烷酮、甲基丙烯酸羟乙酯以及甲基丙烯酸甲酯、甲基丙烯酸乙酯或者甲基丙烯酸丁酯为原料,采用本体共聚法制备共聚物水凝胶角膜接触镜材料,通过材料样品在三油酸甘油酯溶液中浸泡前后的浓度变化,计算沉积量,评价人眼泪液组分三油酸甘油酯在共聚物水凝胶角膜接触镜材料上的沉积作用。结果表明,三油酸甘油酯的沉积量随溶液浓度增大、沉积温度升高、沉积时间延长而增大;共聚物水凝胶材料中N-乙烯吡咯烷酮组分的含量越大,沉积量越大;而甲基丙烯酸甲酯、甲基丙烯酸乙酯或者甲基丙烯酸丁酯组分导致三油酸甘油酯的沉积量减小,以甲基丙烯酸甲酯最为明显。     

水在凝胶中的存在状态及其对凝胶力学性能的影响

以偶氮二异丁腈为引发剂,通过化学引发聚合合成甲基丙烯酸β-羟乙酯（HEMA）/N-乙烯基吡咯烷酮（NVP）二元共聚物和HEMA /NVP /甲基丙烯酸甲酯（或甲基丙烯酸丁酯）三元共聚物水凝胶,通过示差扫描量热法（DSC）结合热重法（TG）研究了不同单体配比的共聚物水凝胶中水的状态,证明了凝胶中存在3种不同状态的水：非冻结结合水、可冻结结合水和可冻结自由水.结果发现可冻结水的含量主要由NVP含量所决定,NVP单元基本不能键合水,而非冻结水的含量主要受HEMA含量和疏水性单体甲基丙烯酸酯含量影响.疏水性单体的引入使材料的力学强度提高,对凝胶体系具有增塑作用的是非冻结水而不是可冻结的结合水和自由水.     

含硅水凝胶角膜接触镜材料的脱水行为

采用重量法研究了γ–（甲基丙烯酰氧）丙基三甲氧基硅烷（KH570）与甲基丙烯酸–2–羟基乙酯（HEMA）及N–乙烯基吡咯烷酮（NVP）共聚物水凝胶角膜接触镜材料的脱水行为。结果表明,含硅水凝胶接触镜材料的脱水机理可采用两种极限情况下的幂律模型来描述,即脱水动力学级数n=0.5和n=1;当n=1时,水凝胶的失水率（Mt/M0c）与时间t成正比,为蒸发阶段;随后的脱水阶段中n=0.5,水凝胶的Mt/M0c与时间t1/2成正比,为扩散阶段;含硅水凝胶接触镜材料的脱水速率随单体NVP和 KH570含量增大而降低,随脱水温度的升高而提高,随盐离子浓度的增加而降低。     

NVP-HEMA-AM三元共聚物水凝胶对氯霉素的缓释作用

采用本体共聚法制备了丙烯酰胺(AM)与甲基丙烯酸-2羟-基乙酯(HEMA)以及N-乙烯基吡咯烷酮(NVP)共聚物水凝胶,研究了AM-HEMA-NVP共聚物水凝胶对广谱抗菌药物氯霉素的缓释作用。结果表明,随氯霉素溶液浓度增大、NaC l浓度降低、温度升高以及NVP或者AM组分的含量增大,AM-HE-MA-NVP三元共聚物水凝胶对氯霉素的吸收量增大;随AM-HEMA-NVP三元共聚物水凝胶中NVP或者AM组分含量的增大,氯霉素的释放速度明显增大;氯霉素从水凝胶中缓释的动力学可采用Fick扩散动力学描述,其释放过程受水凝胶溶胀过程以及氯霉素扩散过程控制。     

共聚物水凝胶接触镜材料与牛血清蛋白亲和性的影响因素

为了评价蛋白质在自行制备的共聚物水凝胶角膜接触镜材料上的沉积行为。将水凝胶膜样品置于牛血清蛋白(BSA)水溶液中,沉积一定时间后,采用染料染色结合分光光度法分析沉积前后牛血清蛋白浓度的变化,计算沉积量。实验发现,随沉积温度升高,牛血清蛋白的沉积量增大;沉积时间超过5天,仍然没有达到饱和沉积;牛血清蛋白的浓度越高,沉积量越大。共聚物水凝胶材料中,N-乙烯吡咯烷酮(NVP)组分的含量越大,沉积量越大;而甲基丙烯酸酯组分则导致牛血清蛋白的沉积量减小,以甲基丙烯酸甲酯(MMA)最为明显。     

温敏型水凝胶的制备及溶胀特性

采用N-异丙基丙烯酰胺(NIPA)与N-乙烯基-2-吡咯烷酮(NVP)为共聚单体,以N,N-亚甲基双丙烯酰胺(BIS)为交联剂,过硫酸钾(KPS)为引发剂,通过化学交联的方法在水溶液中制备出P(NIPA-co-NVP)共聚物水凝胶。分别探讨了单体配比、交联剂用量等实验条件对水凝胶的温敏特性和溶胀性能的影响。利用傅里叶红外(FT-IR)对共聚物水凝胶的结构进行了表征。通过实验可知:当交联剂BIS和引发剂KPS分别为单体用量的5%和0.8%,制备的水凝胶具有较高的转化率、较好的机械强度和共聚性质。共聚物水凝胶中NVP含量越高,溶胀率越大,升温时溶胀率下降程度越大,自然条件下脱水速率越快;BIS用量越大,溶胀率越小,保水率越高,需要更长时间达到溶胀平衡。     

有机硅改性共聚物水凝胶接触镜材料的合成与性能研究

以N-乙烯基吡咯烷酮(NVP)、甲基丙烯酸羟乙酯(HEMA)以及γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH570)为原料单体,N,N’-亚甲基双丙烯酰胺(NMBA)为交联剂,偶氮二异丁氰(AIBN)为引发剂,采用本体聚合法制备有机硅改性共聚物水凝胶接触镜材料,并研究了材料拉伸强度的影响因素。结果表明,所得材料的折光度为1．51,透光率达99%以上;有机硅的引入能显著提高材料的拉伸强度,NVP含量的增加使材料的拉伸强度下降。     

含硅水凝胶膜中Na+的渗透性

采用腔膜法测定Na 在γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH570)与甲基丙烯酸羟乙酯(HEMA)及N-乙烯基吡咯烷酮(NVP)共聚物水凝胶角膜接触镜材料中的渗透系数,研究了Na 渗透系数的影响因素。结果表明,Na 在水凝胶膜中的扩散过程为稳态扩散,其渗透系数随温度升高而显著增大,但温度超过60℃,Na 渗透系数的增大幅度显著下降;水凝胶膜中Na 的渗透系数随NVP及KH570质量分数增多而增大,但KH570的质量分数超过15%,Na 的渗透系数反而随KH570含量增多而减小,其原因在于Na 被聚合物中的微孔陷阱捕获而无法跳出。     

DMAEMA/NVP/HEMA共聚物水凝胶的合成与性能研究

以甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)、N-乙烯基吡咯烷酮(NVP)和甲基丙烯酸β-羟乙酯(HEMA)为共聚单体,采用自由基水溶液聚合法制备了化学交联的三元共聚水凝胶,并对水凝胶在不同温度和不同离子强度及不同pH介质中的溶胀性能进行了测定。结果表明,在不同离子强度(I)的水溶液中,随着I的增大,水凝胶的平衡溶胀比ESR不断降低;但当I>0.2后,对凝胶ESR的影响不显著;当外界环境酸度较大(pH<2)时,凝胶ESR较大,但pH值稍有增大,凝胶ESR迅速下降;温度升高,凝胶ESR减少。     

卷发定型液

GAP公司上市一种阳离子树脂VC-713,系乙烯基已内酰胺/乙烯基吡咯烷酮/甲基丙烯酸二氨基乙酯三元共聚物,以前者为主成分,后二者提供水可溶的阳离子性质,可作烫发后     

NVP-HEMA-KH570共聚水凝胶的合成及其溶胀性能研究

以N,N’-亚甲基双丙烯酰胺为交联剂,偶氮二异丁氰（AIBN）为引发剂,合成不溶于水的乙烯吡咯烷酮（NVP）／甲基丙烯酸β-羟乙酯（HEMA）／γ-（甲基丙烯酰氧）丙基三甲氧基硅烷（KH-570）共聚水凝胶,研究了PVP水凝胶的平衡溶胀度及脱水性能。结果表明,随着NVP在水凝胶中含量的增大,水凝胶的平衡溶胀度逐渐增大;环境温度升高,KH570、BIS的含量及浸泡溶液的离子浓度增大,水凝胶的平衡溶胀度逐渐减少;在相同的时间内,环境温度越高,水凝胶的脱水率也越大;在同一温度下,HE-MA含量越大,凝胶脱水的速度就越慢,而浸泡的溶液离子浓度越高,脱水率就越大。     

Poly(N-vinylpyrrolidone)-grafted poly(N-isopropylacrylamide) copolymers: Synthesis, characterization and rapid deswelling and reswelling behavior of hydrogels

Poly(N-isopropylacrylamide)-block-poly(N-vinylpyrrolidone) diblock copolymer (PNIPAAm-b-PVPy) was successfully synthesized via sequential reversible addition-fragmentation chain transfer/macromolecular design via the interchange of xanthate (RAFT/MADIX) process, in which the chain transfer agent of xanthate was in situ afforded via the reaction of isopropylxanthic disulfide (DIP) with 2,2-azobisisobutylnitrile (AIBN). The RAFT/MADIX technique was employed to prepare the poly(N-vinylpyrrolidone)-grafted poly(N-isopropylacrylamide) copolymers (PNIPAAm-g-PVPy) with N,N-methylenebisacrylamide as the crosslinking agent. The comb-like PNIPAAm-g-PVPy copolymer networks with PVPy as the pendent chains were characterized by means of Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and small angle X-ray scattering (SAXS). The hydrogel behavior of PNIPAAm-g-PVPy networks was investigated in terms of swelling, deswelling and reswelling tests. With the inclusion of PVPy chains, the swelling ratios of the hydrogels were significantly enhanced compared to the control PNIPAAm hydrogel. It is found that the PVPy-modified PNIPAAm hydrogels displayed faster response to the external temperature changes than the control PNIPAAm hydrogel. The improved thermoresponsive properties of hydrogels are ascribed to the formation of the comb-like architectures in the copolymer networks.     

水凝胶-水凝胶复合材料的热分析研究

在甲基丙烯酸羟乙酯单体中加入聚乙二醇400溶胀的交联N-乙烯基吡咯烷酮水凝胶,制备了水凝胶-水凝胶复合材料,采用DSC与TG研究了该复合材料中水的特异性。结果表明,分散相水凝胶与连续相水凝胶的吸水倍率不同,导致复合材料吸水溶胀时不同相结构之间互相制约,复合材料中非冻结水的含量较多,DSC谱图上非冻结水的熔融峰被自由水的熔融峰掩盖;水凝胶中不同存在状态的水的形成与水凝胶的溶胀行为密切相关,非冻结水与中间水的形成都需要足够的空间。     

水凝胶-水凝胶复合材料的制备与表征

将聚乙二醇400(PEG400)溶胀的交联N-乙烯吡咯烷酮(NVP)水凝胶微粒浸渍在含有引发剂过氧化苯甲酰(BPO)的甲基丙烯酸-2-羟基乙酯(HEMA)单体中并加热引发聚合反应,制备水凝胶-水凝胶复合材料,研究了产物的溶胀行为,并采用SEM、DSC对产物进行了表征。结果表明,水凝胶-水凝胶复合材料的饱和含水量随交联NVP水凝胶颗粒的含量及饱和含水量增大而增大,两种水凝胶之间的界面结构可分为包埋、部分互穿网络以及完全部分互穿网络等三种,其原因在于HEMA单体部分进入交联NVP水凝胶微粒并进行原位聚合的程度不同;处于分散相的水凝胶与处于连续相的水凝胶的吸水倍率不同,导致水凝胶-水凝胶复合材料吸水溶胀时不同相结构之间互相制约,处于分散相的水凝胶的大分子链不能充分伸展,非冻结水的熔融峰被自由水的熔融峰掩盖,表现为DSC谱图上非冻结水的熔融峰被自由水的熔融峰掩盖。     

Atom transfer radical polymerization of some vinyl monomers catalyzed by imine macrocycle copper (I) complex

Summary Imine macrocyclic ligand (M₁) was used in conjunction with CuBr as novel catalytic system in atom transfer radical polymerization (ATRP) of methylmethacrylate (MMA), butylmethacrylate (n-BuMA) and 2- dimethylaminoethylmethacrylate (DMAEMA). Two different initiators were involved such as Br-methoxypolyoxyethylene macroinitiator and 1, 3, 5-(2-bromo-2‘-methylpropionato) benzene three arm star initiator. The polymerization reactions were conducted at 90 °C in toluene. The macrocyclic ligand M₁ demonstrated peculiar behavior which was monitored by the GPC measurements whether with respect to the polydispersities or the molar masses. High molar masses than expected were obtained except incase of DMAEMA monomer. The structures of the formed polymers were proven via ¹HNMR.     

Synthesis and Properties of Electroactive Polyaniline-Graft Polymethyl Methacrylate Copolymer by Atom Transfer Radical Polymerization

In this research, N-substituted polyaniline was synthesized by chlorine-terminated chloroacetyl chloride incorporation and methylmethacrylate polymerization done onto the leucoemeraldine. The authors prepared polyaniline-graft-polymethylmethacrylate copolymer by methylmethacrylate ATRP using polyaniline macroinitiator. First, polyaniline was prepared by chemical oxidation. The macroinitiator was synthesized via reaction of leucoemeraldine's nitrogen with chloroacetyl chloride. Macroinitiator and graft copolymer were characterized by FT-IR and ¹H-NMR. SEM and AFM images showed the growing of poly methylmethacrylate chains on polyaniline backbone. Solubility test revealed that polyaniline-graft-poly(methylmethacrylate) was in some organic solvents. CV study confirmed this copolymer was electroactive. Elemental analysis determined the amount of grafting polymethylmethacrylate on leucoemeraldine.     

Temperature influence and CO2 transport in foaming processes of poly(methyl methacrylate)–block copolymer nanocellular and microcellular foams

Fabricated by high-pressure or supercritical CO₂ gas dissolution foaming process, nanocellular and microcellular polymer foams based on poly(methyl methacrylate) (PMMA homopolymer) present a controlled nucleation mechanism by the addition of a methylmethacrylate–butylacrylate–methylmethacrylate block copolymer (MAM), leading to defined nanocellular morphologies templated by the nanostructuration of PMMA/MAM precursor blends. Influence of the CO₂ saturation temperature on the foaming mechanism and on the foam structure has been studied in 90/10 PMMA/MAM blends and also in the neat (amorphous) PMMA or (nanostructured) MAM polymers, in order to understand the role of the MAM nanostructuration in the cell growth and coalescence phenomena. CO₂ uptake and desorption measurements on series of block copolymer/homopolymer blend samples show a competitive behavior of the soft, rubbery, and CO₂-philic block of PBA (poly(butyl acrylate)) domains: fast desorption kinetics but higher initial saturation. This competition nevertheless is strongly influenced by the type of dispersion of PBA (e.g. micellar or lamellar) and a very consequent influence on foaming.CO₂ sorption and desorption were characterized in order to provide a better understanding of the role of the block copolymer on the foaming stages. Poly(butyl acrylate) blocks are shown to have a faster CO₂ diffusion rate than poly(methyl methacrylate) but are more CO₂-philic. Thus gas saturation and cell nucleation (heterogeneous) are more affected by the PBA block while cell coalescence is more affected by the PMMA phases (in the copolymer blocks + in the matrix).