F68大单体/HEMA共聚水凝胶的制备及性能研究(Ⅰ):温度敏感性

本文以温度敏感性Pluronic F68与甲基丙烯酸缩水甘油酯(GMA)反应制备可光聚合的F68/GMA大分子单体,再在水溶液中与丙烯酸(AA)单体和甲基丙烯酸β-羟乙酯(HEMA)经紫外光原位聚合制备温度敏感水凝胶。详细地研究了水凝胶在不同温度下的溶胀性能。溶胀动力学测量的结果表明,该水凝胶具有温度响应性且具有可逆性。     

一种新型水煤浆聚羧酸分散剂大单体的制备

为探索一种优化的聚羧酸系分散剂大单体生产工艺,以衣康酸、聚乙二醇为原料,考察了反应物配比、反应时间、反应温度、催化剂对活性大单体酯化率的影响。实验表明,较佳反应条件为:催化剂为对甲苯磺酸,n(衣康酸)∶n(聚乙二醇)=1∶1.5,反应温度为85℃,反应时间5 h。表面性能研究结果表明,该表面活性剂有较好的表面活性,在25℃下c,mc为5.01 mmol/L,在cmc时的γ=47.1 mN/m,Krafft点<0℃。     

大单体技术合成甲基丙烯酸甲酯—丙烯酸丁酯规整接枝共聚物

采用大单体技术合成了以聚甲基丙烯酸甲酯（PMMA）为主链,聚丙烯酸丁酯（PBA）为支0甸的规整接枝共聚物。产物提纯后用红外光谱表征结构。研究了封端反应时间,体系浓度对封端效率的影响以及PBA大单体与投料总量的质量比,引发剂用量,共聚反应温度对接枝效率的影响,还研究了接枝共聚物的力学性能,当聚丙烯酸丁酯大单体的相对分子质量大于5000,PBA大单体与投料总量的质量比约为60％时,此接枝共聚物是一种性能良好的热塑性弹性体。     

Synthesis,characterization, and properties of amphiphilic poly(ethyl acrylate) with uniform polyoxyethylene grafts

Amphiphilic copolymers of ethyl acrylate (EA) with uniform polyoxyethylene (PEO) grafts were synthesized by copolymerization of EA with methacrylate terminated PEO macromer in benzene using azobisisobutyronitrile as the initiator. The effects of the molecular weight of the macromers, the charging weight ratio of the macromer to EA, the total monomer concentration, and the amount of initiator on the grafting efficiency (GE) were reported as was the molecular weight of the copolymers. The highest GE reached to above 90% and the molecular weight of the copolymers varied from (5–15) × 10⁴. The reactivity ratio of EA with the macromer was determined to be 0.83. The graft copolymers were purified with extractions and the purified products were characterized with IR, ¹H‐NMR, gel permeation chromatography, differential scanning calorimetry, and membrane osmometry. The average grafting number of the copolymer varied from 2 to 11. The glass‐transition temperature of the poly(EA) in the copolymer was increased because of the partial compatibility of the two components. The crystalline property, emulsifying property, and dilute solution viscosity of the graft copolymers, as well as ionic conductivity of their complexes with alkali metal salts, were studied. The emulsifying volume decreased with the increasing molecular weight of the PEO grafts. The addition of NaOH to the emulsion affected the emulsifying volume only slightly, whereas the addition of HCl changed the oil in water type emulsion into a water in oil type. The conductivity of the LiClO₄ complex of the copolymer with an oxyethylene/Li ratio of 20 reached 3.7 × 10^?5 S/cm at 27°C. The lower the crystallinity of the complex, the higher was the conductivity. The dilute solution viscosity showed the existence of intramolecular microphase separation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 903–912, 2001     

Transparent organic materials made from copolymerization of styrene with urethane‐methacrylate macromer. III. Thermal behaviors

Urethane‐methacrylate macromers were prepared by the reaction of tolylene diisocyanate with various glycols, followed by end capping with 2‐hydroxyethyl methacrylate. A new transparent polymeric material was fabricated by the copolymerization of the macromers with styrene. The thermal behaviors of the new material were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analysis. The samples with different distances between crosslinking points exhibited different thermal behaviors. The sample with short segments between the crosslinking points had a homogenous phase structure and displayed only one glass transition. For the sample with long segments between the crosslinking points, there was a major glass transition and a minor relaxation at high temperature. Surprisingly, the sample with moderate length segments between the crosslinking points showed a novel exothermic peak in the DSC curve. The exothermic peak may have resulted from the formation of a special physical interaction, such as a hydrogen bond. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 680–686, 2001     

Preparation of semi‐interpenetrating polymer networks composed of silk fibroin and poly(ethylene glycol) macromer

Semi‐interpenetrating polymer networks (SIPNs) composed of silk fibroin (SF) and a poly(ethylene glycol) (PEG) diacrylate macromer were synthesized and characterized. The conformation of SF in SIPNs was changed from a random coil to a β‐sheet structure by formation of SIPNs with PEG, while the crystalline structures of SF and PEG in SIPNs was not changed. The decomposition temperature of SF in the SIPNs was inner‐shifted, an indication of SIPN formation between the SF and the PEG macromer. The tensile strength and elongation of the SIPNs were much higher than were those of SF itself or the SF/PEG blend and increased with an increase of the PEG content. The equilibrium water content of SF was remarkably increased by formation of SIPNs with PEG due to the hydrophilic property of PEG. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1848–1853, 2001     

Fiber formation from semi‐interpenetrating polymer networks consisting of polycaprolactone and a poly(ethylene glycol) macromer

Semi‐interpenetrating polymer networks (SIPNs) consisting of polycaprolactone (PCL) and poly(ethyleneglycol) (PEG) macromer was prepared to improve tensile property in developing biodegradable sutures. When the PEG macromer formed SIPNs with PCL, biodegradability, mechanical strength, and hydrophilicity were improved. The SIPNs fibers formed from the dry spinning process showed an increase of not only tensile strength but also water content with an increase of PEG content. These results represent an increase of the crosslinking density of the PEG network with hydrophobic property. The drawing of SIPNs fibers also further enhanced the tensile strength and the crystallinity of the SIPNs fibers. Unimelting temperature of the SIPNs fiber was observed as an indication of the polymer network without phase separation. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 835–841, 2002; DOI 10.1002/app.10351     

甲基丙烯酸甲酯与丙烯酸丁酯规整接枝共聚物的合成及性能研究

采用聚丙烯酸丁酯大分子单体和甲基丙烯酸甲酯小分子单体共聚 ,合成了以甲基丙酸甲酯为主链、丙烯酸丁酯为支链的规整接枝共聚物。用红外光谱表征结构 ,研究了大单体的投料量、引发剂的用量及共聚反应温度对接枝效率的影响。并且研究了接枝共聚物的力学性能影响因素 ,当聚丙烯酸丁酯大单体的分子量大于 50 0 0 ,投料重量百分比在 6 0 %左右 ,得到性能良好的热塑性弹性体     

Polyoxyethylenic macromers from polyoxyethylene monomethyl ethers and isocyanatoethyl methacrylate. Synthesis and characterization of copolymers with styrene and methyl methacrylate, obtained through bulk, solution and soap-free emulsion polymerizations

Polyoxyethylenic (POE) macromers were prepared from polyoxyethylene methyl ethers and isocyanatoethyl methacrylate and characterized by ¹³C and ¹H nuclear magnetic resonance spectroscopy. Copolymers with styrene and methyl methacrylate (MMA) were obtained from these macromers upon free-radical initiation under various conditions (solution, bulk, soap-free emulsion) and some physical properties were studied (e.g. glass transition temperatures, stability of latex). Phase separation was observed in some copolymers with MMA as determined through dilatometry. Polystyrene latices, prepared without any emulsifying agent other than POE macromers themselves, were stable in the presence of high electrolyte concentrations.     

Synthesis and reactions of methacryl-substituted siloxane macromers

Copolymerizations of two methacryl-terminated siloxane macromers (M _n=4000 and 23,00 g/mol) with styrene monomer were studied as a model of how reactive silicones may cross-link with unsaturated polyesters. Significant differences were found between the two macromers in the nature of the polymerization, the rate of reaction, the cloud point, and the products formed. The lower molecular weight macromer freely cross-links to form an insoluble three-dimensional network with styrene. The high molecular weight macromer reacts at only one terminal methacryl group and so forms a two-dimensional copolymer with styrene which melts like a thermoplastic and is soluble in organic solvents such as chloroform.This paper was presented at the Second International Topical Workshop, Advances in Silicon-Based Polymer Science.