Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperature. I. Optical strain of thermal stream type

It was found previously that cast articles of transparent polymer without optical strain could be obtained efficiently in a very short time by radiation-induced polymerization of glass-forming monomers at low temperature. Two types of optical strain were observed in casting of these monomers: thermal stream type and remaining (inner) stress type strain. The mechanism of thermal stream-type strain formation was investigated by following the heat and temperature change during cast polymerization in this report. It was found that the temperature difference between the upper and lower part of the sample was large and the temperature was much higher in the upper part than in the lower part under conditions of strain formation. Increase of heat removal from the sample surface decreased the temperature difference in the vertical direction and reduced the strain formation. It could be deduced that stream-type strain formed as a result of thermal stream and it was retarded in radiation casting of glass-forming monomers owing to high viscosity and low temperature.     

Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperatures. IV. Casting and polymer properties of monomeric systems including polyfunctional monomers

The applicability to radiation-induced cast polymerization of polyfunctional monomers or systems including them was studied. Most of polyfunctional monomers could be glassified and were applicable to radiation casting. The effect of tetraethylene glycol diacrylate on inner-plasticized comonomer systems was studied in detail. It was found that the glass-forming property increased by the addition of tetraethylene glycol diacrylate and that heat durability improved satisfactorily. The formation of optical strain in casting was relatively easier in polyfunctional monomers including systems due to inner stress, although the merit of radiation casting was still obvious.     

Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperatures. III. Casting and polymer properties of monomer systems including inner-plasticizing comonomers

Previously, it was found that organic glass material having no optical strain could be cast efficiently in a very short time by radiation-induced cast polymerization of glass-forming monomers. In this report, practical useful monomer systems having glass-forming property and good physical properties were investigated. Several inner plasticized comonomer systems of excellent impact resistance were found which could be glassified and applied to radiation casting. These systems included butyl acrylate or hexanediol monoacrylate as inner plasticized component. Physical properties other than impact resistance were tested. The casting polymerization was studied, and it was found that polymers without optical strain could be obtained in a remarkably short time.     

Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperatures. VI. Casting polymerization of methyl methacrylate prepolymer by irradiation

Casting of methyl methacrylate prepolymer by irradiation at relatively low temperatures was studied. It was difficult to completely glassify the methyl methacrylate monomer and prepolymer, and so the casting was carried out at temperatures above its melting point (?48°C). The optical strain formed in this stream remained of the stress type, and optical strain formation was reduced with increasing prepolymer concentration and decreasing temperature.     

Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperatures. V. Casting and polymer properties of CR-39 modified monomer systems

Glassification, cast polymerization, and physical properties of monomeric system including diethylene-glycolbisallyl carbonate (CR-39) was investigated. Addition of other monomers CR-39 was investigated CR39- polyfunctional monomer and CR-39-methyl methacrylate-polyfunctional monomer systems were found to form stable glassy state applicable to radiation-induced casting and good in physical property. Two-step polymerization method consisting of pre-irradiation and post-catalytic polymerization necessary to complete casting. It was found that these newly found CR-39 modified systems could be casted efficiently in much shorter time cycle than catalytic process without forming optical strain. Physical properties of casted polymer such as impact resistance and heat durability were sufficient for practical use.     

Cast and mold polymerization of organic glass by irradiation from fluid and soft gel prepolymers

Casting and mold polymerization processes were investigated by means of γ-irradiation of methyl methacrylate prepolymer systems containing some quantity of polyfunctional monomers. Some physical properties, such as supercooling tendency and temperature dependence of viscosity and relaxation time in fluid prepolymers, were measured and related to cast polymerization at low temperatures. It was found that free-state casting with no frame or mold was possible using viscous states of prepolymer in the supercooled state. Furthermore, efficient mold polymerization using soft gel prepolymer was studied. That is, plastic soft gel prepolymer was prepared conveniently by irradiation of fluid prepolymer, then molded into spherical or nonspherical curved surface shapes, and curved by reirradiation. Polymerization and gelation behavior of soft gel prepolymer and penetration degree of prepolymer as a measure of plasticity of gel were studied in relation to prepolymer composition and irradiation condition.     

New coating materials prepared by radiation-induced polymerization. II. Study on the polymerization mechanism of mar-resistant coating composition

It was previously reported that excellent mar resistance coating systems could be obtained by the combination of silicone compounds and vinyl compounds, such as KBM 403–GMA systems. Radiation-induced polymerization was the most efficient means of prepolymerization of give the viscosity suitable for coating. In this report, change in conversion and the predominant mechanims of prepolymerization were investigated by measuring the change in refractive index. It was shown that the conversion change and the predominant prepolymerization mechanism could be identified by the refractive index. The relationship between the refractive index and coating properties such as film thickness and haze value was also studied. Dripping of GMA prepolymer occurred, and coating thickness was small in GMA including prepolymer systems obtained predominantly by radical mechanism; the thickness was relatively large in the prepolymer systems obtained by epoxy ring opening-type polymerization mechanism. However, the mar resistance in the former was excellent in spite of reduced thickness.     

Preparation of Fresnel lenses by radiation cast polymerization

Preparation of Fresnel lenses was investigated applying radiation polymerization of methyl methacrylate prepolymer systems containing polyfunctional monomers. Line focus Fresnel lenses 75 × 75 cm could be prepared in very short time cycles with sufficient exactness by radiation cast polymerization, preferably at low temperatures. Preparation of Fresnel lenses could be carried out also very easily and efficiently by printing the soft plastic prepolymer sheet with a Fresnel lenses mold and then curing it by irradiation.     

Immobilization of enzymes by radiation-induced polymerization of glass-forming monomers: 1. Immobilization of some enzymes by poly(2-hydroxyethyl methacrylate)

The immobilization of some enzymes has been studied by radiation-induced polymerization using 2-hydroxyethyl methacrylate as a glass-forming monomer. Radiation damage of enzymes was slight after irradiation at low temperatures. Moreover, the activity yield of immobilized enzymes increased markedly at polymerization temperatures below ?24°C. The polymer formed was characterized by its porous structure which was studied in detail in relation to the activity yield and its activity retention with repeated use. It was deduced that enzymes were partly trapped at the pore surface within the polymer matrix and partly within the pores from which they were able to leak out with repeated use. Hence, the use of low temperature and super-cooled monomer was necessary for effective enzyme immobilization.     

Mechanistic investigation of the simultaneous addition and free-radical polymerization in batch miniemulsion droplets: Monte Carlo simulation versus experimental data in polyurethane/acrylic systems

A detailed kinetic Monte Carlo simulation was used to predict the characteristics of the batch miniemulsion polymerization of an isocyanate and an acrylic monomer mixture that contains a hydroxyl functional monomer (HEMA). The simulation takes into account the simultaneous polyaddition of the polyurethane prepolymer with the hydroxyl group of HEMA and the free radical polymerization of the acrylic monomers and all reactions in aqueous and polymer particle phases. The model has been assessed by batch miniemulsion polymerizations carried out using an aliphatic isocyanate prepolymer, n-butyl acrylate, 2-hydroxyethyl methacrylate monomers and potassium persulfate as an initiator. It was found that partitioning of water had a significant effect on both kinetics and microstructure of the resulting polymer. Evolution of different species of PU prepolymer produced in the reaction and the sol and gel fractions revealed that the terminal pendent double bond of the HEMA in polymer chains has significantly lower reactivity than that of the HEMA free monomer. Detailed information on gel microstructure has been derived in the model by both distribution of molecular weight between crosslinking points in acrylic chains and distribution of chain extension of PU prepolymers. These crosslinking density distributions can be related to mechanical and adhesive properties of the polymer.     

New one-step process for preparation of microporous composite polysulfone/polyurethane hollow-fiber membranes

Microporous composite polysulfone/polyurethane hollow-fiber membranes were prepared by using a low reactivity polyurethane prepolymer in the casting solution and precipitating the membrane in a precipitation solution containing a polymerization catalyst. The catalyst was used to promote the polymerization of prepolymer at the membrane/precipitation solution interface causing formation of an interfacial interpenetrating polymer network. As a result, an ultra-thin layer of hydrophilic polysulfone/ polyurethane composite polymer was constituted in situ on the surface of the polysulfone microporous substrate during membrane formation. Membranes with nominal pore sizes ranging from 0.1–0.45 μm were prepared using this technique. The resulting membranes exhibited excellent fluxes and very low protein adsorption characteristics.     

Radiation-induced solid-state polymerization in binary systems. VII. Polymerization in solid–liquid equilibrium phase containing long-chain compounds

The radiation-induced polymerization of binary systems consisting of vinyl monomers (mainly methyl methacrylate) and various long-chain compounds in solid–liquid equilibrium state has been studied. Phase diagrams of these systems showed that all systems containing long-chain compounds form a complete crystalline phase at temperatures below the solidus line. It was found that remarkable acceleration of the polymerization occurred in the solid–liquid equilibrium state. The long-chain compounds are classified into three groups according to the acceleration effect. The group including paraffin, long-chain esters, and cetyl alcohol exerted the largest acceleration effect over wide temperature regions at which the solid–liquid equilibrium exists. Maximum polymerization rate was observed at temperatures below the melting point in the presence of long-chain compounds of the above-mentioned group. It was observed in this case that the long-chain compounds crystallized to form very fine colloidal particles and the system was soft and waxy in the solid–liquid equilibrium state. The acceleration of the polymerization in the binary system consisting of a vinyl monomer and a compound having no long-chain substituents or in the homogeneous solution consisting of monomer and viscous solvent were far less than that in the presence of long-chain compounds. It is suggested that the effect can be attributed to the effect of a special reaction matrix favorable to polymerization in the solid–liquid equilibrium.     

甲基丙烯酸甲酯-苯乙烯-马来酸酐三元共聚物的本体转移悬浮聚合法

本研究采用本体转移悬浮聚合法合成苯乙烯(ST)-甲基丙烯酸甲酯(MMA)-马来酸酐(MAH)三元共聚物。本聚合法结合了本体聚合和悬浮聚合的优点,通过本体预聚降低马来酸酐水解程度,制备了高酸酐含量的三元共聚产物,研究了引发剂、分散剂用量和预聚转化率对反应的影响,并比较不同单体比例与最终产物的性能关系。     

小形变下聚氨酯/聚氨基甲酸酯纤维复合材料的增强和阻尼性

利用聚氨基甲酸酯纤维织物、3,3′-二氯-4,4′-二氨基二苯基甲烷(MOCA)分别与聚丙二醇(PPG)型预聚体和聚四氢呋喃醚二醇(PTMG)型预聚体经浇注一体成型制备聚氨酯/聚氨基甲酸酯纤维复合材料,研究了聚氨基甲酸酯纤维织物对聚氨酯基体小形变下的抗张应力和阻尼性能的影响。结果表明,聚氨基甲酸酯纤维织物对聚氨酯基体小形变下的抗张应力和阻尼性能均具有明显的增强作用;与各自基体相比,PPG型和PTMG型复合材料的弹性模量分别提高了16.33 %和11.39 %,其 100 %定伸应力分别提高了55.81 %和46.51 %;而且二者的一次拉伸回复滞后率分别高达55.10 %和62.83 %,较各自基体分别提高了26.12 %和14.03 %。     

Interpenetrating polymer network of blocked polyurethane and phenolic resin. I. Synthesis,morphology, and mechanical properties

Interpenetrating polymer networks (IPNs) based on blocked polyurethane (BPU)/phenolic (PF) were prepared using simultaneous polymerization method. The IPN was prepared from BPU prepolymer with m‐xylylenediamine as the chain extender and PF prepolymer using p‐toluene sulfonic acid as a catalyst. From Fourier transform infrared spectra analysis, it was found that the major reactions in the BPU/PF IPN system are the polymerization of BPU/MXDA and the self‐polymerization of PF. It was confirmed from scanning electron micrography that the BPU/PF IPN compatibility of the networks was improved, and the system was heterogeneous and more than one phase existed in the IPN. The tensile properties, flexural properties, impact, and hardness of the prepared IPN were studied. To obtain the best mechanical properties of IPN materials, the filler added in IPN materials has to be investigated. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

纯有机亲水铝箔涂覆材料的制备研究

介绍了一种纯有机亲水铝箔涂料的制备及研究。对亲水树脂的制备方法进行了改进,并通过实验确定:聚醚预聚体与聚氨酯预聚体投料质量比为1∶1;聚合时聚醚预聚体宜加于釜底;应增大乙烯基磺酸钠单体的加入比例。研究了亲水涂料的调配及涂装工艺,确定亲水树脂与表面活性剂吐温-60的质量比在8~10、涂料的pH值在6~6.5,铝箔经汽油漂洗、碱液浸泡脱脂预处理,成膜温度在250℃时,涂膜持续亲水性能优异。     

Optimizing polymer reactivities for the solid-state polycondensation of AA and BB type monomers

A new method is presented to optimize the reactivities of a prepolymer for the solid-state polymerization of AA and BB type monomers to obtain high molecular weight polymers. The proposed method consists of blending the prepolymers of different end group mole ratios to maintain optimal reaction stoichiometry, and developing a computational procedure to calculate the molecular weight of the polymer in the solid-state polymerization. A molecular species model is used to calculate the molecular weight moments of the optimized prepolymer and to calculate the molecular weight development in a solid-state polymerization. The molecular weight moments of different polymer species in the prepolymer mixture are estimated by performing the dynamic simulations of a melt prepolymerization process model in conjunction with a numerical optimizer. The model simulation results show that the proposed method offers a significantly improved process performance to obtain high molecular weight condensation polymers in a solid-state polymerization. Bisphenol A polycarbonate is selected as an example to illustrate the proposed method.     

Controlled release of biofunctional substances by radiation-induced polymerization: 2. Release of potassium chloride from porous poly(diethylene glycol dimethacrylate)

The controlled release of potassium chloride from flat circular matrices made by radiation-induced polymerization of a glass-forming monomer at low temperatures has been studied. The water-particle phase content formed in a poly(diethylene glycol dimethacrylate) (polyDGDA) matrix was controlled by the addition of polyethylene glycol #600 (PEG 600). The dispersed water-particle phase content in the matrix was estimated directly and by scanning electron microscopic observations. The release of potassium chloride from the matrix increased linearly with the square root of time. The water content of the matrix had an important effect on the release rate which increase roughly in proportional to water content. This effect can be attributed to the apparent increase of the rate of drug diffusion.     

新型紫外线固化环氧树脂/丙烯酸酯改性水性聚氨酯的合成与性能

合成了一种新型的具有高交联密度和优异涂膜性能的环氧树脂和丙烯酸酯同时改性的紫外线（UV）固化水性聚氨酯（UV-EP-AC-WPUD）。通过环氧基团与以异氰酸酯基团（-N=C=O）封端的聚氨酯预聚体之间的反应引入质量分数为4%的环氧树脂E-20。同时,通过聚氨酯链的-N=C=O与二元丙烯酸酯（PEDA）以及季戊四醇三丙烯酸酯（PETA）的羟基之间的反应引入碳碳双键（C=C）,C=C的含量达到4.65 meq·g-1。 质量分数为3%的光引发剂Irgacure 2959被用于引发涂膜中C=C的聚合,涂膜的凝胶含量在12 s UV辐射之后达到91%,意味着C=C的聚合和交联速度快,同时所得到的涂膜的交联度非常高,不溶于溶剂丙酮,测试表明环氧树脂和两种丙烯酸酯单体已经成功嵌入聚氨酯链中,涂膜具有优异的力学性能和化学性能。     

水性聚氨酯聚丙烯酸酯细乳液的制备及在调湿涂料中的应用

首先以聚氧化丙烯二醇(PPG)、异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)为主要单体,甲基丙烯酸羟乙酯(HEMA)为接枝试剂,合成了接枝聚氨酯预聚体(PU-HEMA),进一步与丙烯酸酯进行共聚反应,制备了水性聚氨酯/聚丙烯酸酯(PU-PA)细乳液。考察了单体用量及PA/PU质量比对乳液性能的影响,发现DMPA、HEMA最佳用量分别为3%和6%。采用FTIR、TG、SEM对PU-PA进行了表征。然后以PU-PA为成膜物,硅藻土、膨润土等为颜填料,所制备的PU-PA调湿涂料(PU-PA-C)性能达到国家内墙涂料和建筑涂料标准,其耐洗刷性大于900次,最大吸水率达到206%。该涂料吸/放湿(水)性能强,可用于室内调湿涂料的涂刷。