Syntheses and cured films properties of UV-autocurable BTDA-based multiacrylate resins

A series of UV-autocurable 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and benzophenone tetracarboxylic acid (BTAc)-based multiacrylate resins containing pendant glycidyl methacrylate (GMA) or glycidyl acrylate (GA) and 2-hydroxyethyl acrylate (HEA) or 2-hydroxyethyl methacrylate (HEMA) were synthesized. The effects of the acrylic functional groups, the moles of GMA, and the molar ratio of HEMA/HEA on their properties were investigated. The prepared autocurable resins are cured rapidly when exposed to UV or sunlight radiation without addition of any photoinitiator or Photosensitizer and the acrylate-type resin resulted in a lower thermal curing temperature and a fast curing rate. Increasing the moles of GMA or the molar ratio of HEMA/HEA on reaction leads to a higher cross-linking density and resulted in film with a higher Young's modulus, breaking strength, and lower elongation. The methacrylate-type resin cured to a very hard, but brittle film with a higher Young's modulus and lower elongation. However, the acrylate-type resin cured to a hard tough film with a lower Young's modulus and higher elongation. The cured methacrylate-type resin results in a lower weight loss at temperature below 300°C due to a higher cross-linking density and lower residual weight percent at 600°C due to the lower percent of benzene rings in the resin. The film properties of the resins coated on steel plates were also investigated. © 1994 John Wiley & Sons, Inc.     

Preparation and properties of UV-autocurable BTDA-based epoxy-multiacrylate resins. Effects of the degree of polymerization and the epoxy type

A series of UV-autocurable epoxy-multiacrylate resins was synthesized, and the effects of degree of polymerization (DP) and epoxy type on their properties were investigated. These autocurable multiacrylate resins possess good pot life and are cured rapidly when exposed to ultraviolet (UV) without the addition of photoinitiator or photosensitizer. The curing rate of the autocurable resins was probably dependent on the number of abstractable hydrogen in epoxy resins. Stress-strain, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA) were used to characterize the properties of cured multiacrylate resins. Increased crosslinking density of cured films improved tensile properties. Increasing the molar ratio of epoxy resin in the multiacrylate resins was found to decrease the effective acrylate concentration of resins and to depress crosslinking density of cured resins, which also resulted in an increased elongation at break but a decreased Young's modulus and breaking strength. Furthermore, the different structures of epoxy resins were used to give wide range properties of cured epoxy-multiacrylate resins with a glass transition temperature (T_g range from 74 to 102°C. The film properties of the multiacrylate resins coated on steel plates were also investigated.     

Syntheses and properties of UV-autocurable BTDA-based polyester multiacrylates. II. Effect of polyol type and reactive monomer

Several families of UV-autocurable benzophenone tetracarboxylic dianhydride (BTDA)-based polyester multiacrylate oligomers containing pendant glycidyl methacrylate (GMA) were synthesized and the effects of acrylic functionality and polyol type on their properties were investigated. The obtained autocurable oligomers possess good pot life and are cured rapidly when exposed to ultraviolet (UV) radiation without the addition of photoinitiator or photosensitizer. Different polyols were used to obtain wide range properties of cured multiacrylate oligomers with a glass transition temperature (T_g) range of 84–130°C. A further modification of the multiacrylate oligomers was obtained by mixing them with reactive monomers having different molecular structure and methacrylic functionality.     

Preparation and properties of UV-curable polyurethane acrylates

UV-curable polyurethane (PU) acrylates have been synthesized from polypropylene glycol (PPG), isophoron diisocyanate (IPDI), and three types of reactive diluents, i.e., 2-hydroxyethylacrylate (HEA), tripropyleneglycol diacrylate (TPGDA), and trimethylolpropane triacrylate (TMPTA). The effects of soft segment length, type, and concentration of reactive diluent on the mechanical and dynamic mechanical properties have been determined. When the soft segment length was short (750) tensile strength (σ_b) decreased, and elongation at break (ϵ_b) generally increased with increasing HEA concentration, due respectively to the inferior strength of HEA homopolymer, and increased molecular weight between crosslinks (M_c). Initial modulus (E) and σ_b increase and elongation at break (ϵ_b) decreased with the increase of TPGDA concentration, and the effect was more pronounced as the soft segment length decreased. The hardness and σ_b increase with diluent concentration in PPG 2000-based materials was more pronounced with higher functionality diluent, due to the increased crosslinking density. The lower temperature glass transition peak of PU was not influenced by the TPGDA incorporation, whereas the higher temperature one moved toward still higher temperature. This was interpreted in terms of possible compatibility of hard segments and acrylates due to their similar polarity and hydrogen bonding. © 1996 John Wiley & Sons, Inc.     

Preparation and properties of dual-cure polyurethane acrylate

Dual-cure polyurethane acrylates (PUA) with different double bonds content were synthesized by using aliphatic polyisocyanate and 2-hydroxyethyl acrylate (HEA). The molecular structures were identified by Fourier transform infrared (FTIR) spectrum and nuclear magnetic resonance (NMR). Molecular weight (M_w) and glass-transition temperature (T_g) of PUA were measured by gel permeation chromatography and DSC, respectively. The pendulum hardness, pencil hardness, flexibility and abrasion resistance properties of dual-cure system were tested, the results indicated that the pendulum hardness, pencil hardness, and MEK resistance increased, but the flexibility reduced with the double bonds content increased. The mechanical properties of dual-cure system were greatly improved after the heat treatment.     

Syntheses and properties of UV-autocurable prepolymers. Semicrystalline urethane-multiacrylates

A series of UV-autocurable urethane-multiacrylate prepolymers, which were semicrystalline and showed melting points in the region of 40–50°C, was synthesized. Also, the effects of curing temperature and acrylic functionality on the structure and properties of the cured films were investigated. These prepolymers are solids and opaque at room temperature. In general, UV curing reactions of solid prepolymers are less efficient when compared with those of liquid prepolymers. UV curing reactions at curing temperatures below the melting point (T_m) of the prepolymers produced semicrystalline urethane-multiacrylate cured films. On the contrary, UV curing reactions above T_m destroyed the crystalline phase of the prepolymers and improved the transparency of the cured films. The films cured below T_m of the prepolymers had higher both breaking strength and Young's modulus, and a higher glass transition temperature (T_g), but a lower elongation at break than those cured above T_m. Such curing temperature effects were attributed to the retention or disappearance of the crystalline structure of the prepolymers during UV curing reaction. At curing temperatures below T_m, an increase in acrylic functionality of the prepolymer resulted in a fast curing rate and a higher crosslinking density of the cured films. Therefore, an increase in acrylic functionality of the prepolymers gave cured films with higher breaking strength and Young's modulus, but a lower elongation at break.     

Preparation and properties of UV-curable polyurethane acrylate ionomers

Ultraviolet (UV)-curable polyurethane acrylate ionomer (PUAI) prepolymers were synthesized from isophorone diisocyanate (IPDI), poly(methylene ether) glycol (PTMG), 2,2-bis(hydroxymethyl) propionic acid (DMPA), triethylamine (TEA), 2-hydroxy ethyl acrylate (HEA), and dibutyl tin dilaurate (DBT) as a catalyst. UV-curable polyurethane acrylate ionomer aqueous dispersion was formulated from the prepolymers, water (30 wt %), and 1-hydroxycyclohexylhenyl ketone (Irgacure 184) as a photoinitiator. The films of UV-cured polyurethane acrylate ionomer were formed by curing the dispersion using a medium-pressure mercury lamp (80 W/cm; λ max = 365 nm). Gel content decreased with increasing water content in the aqueous dispersion. Effects of DMPA content and molecular weight of PTMG and the degree of neutralization on the physical properties were investigated. It was found that the storage modulus increased with increasing DMPA content. Tensile modulus and strength decreased with increasing the molecular weight of PTMG from 650 to 2000. The glass transition temperature shifted to a higher temperature as the content of DMPA increased. As the degree of neutralization increased, the tensile strength and modulus decreased. However, the elongation at break increased. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:2153–2162, 1998     

Preparation and properties of waterborne cationic fluorinated polyurethane

Waterborne cationic fluorinated polyurethane (WCFPU) micro-emulsion was prepared by the reaction of isophorone diisocyanate (IPDI), polytetramethyleneether glycol (PTMG1000), 1,4-butanediol (BDO), N-methyldiethanolamine (MDEA), trimethylolpropane (TMP) and perfluoroalkylethyl octanol (FEOH), and then the films of the WCFPU were prepared. The influence on the mechanical properties and water absorption of the films, such as the molar ratio of NCO to OH, the dosage of MDEA, TMP and FEOH, was investigated. Their structure, morphology and heat performance were characterized by fourier transform infared spectrometer (FT-IR), dynamic light scattering (DLS), transmission electron microscope (TEM), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and thermogravimetry (TG). The results revealed that the best mechanical properties and water resistance could be obtained under the condition that NCO/OH molar ratio was 1.25, w(TMP) was 1.1%, w(MDEA) was 7.29% and w(FEOH) was 22.3%. In addition, WCFPU was endowed with low surface energy of its film and the membrane surfaces had excellent water and oil repellency. Furthermore, the thermal stability of the waterborne cationic fluorinated polyurethane increased with the incorporation of perfluoroalkyl chain. And XRD, DSC and TG showed that micro-crystallinity of polyurethane increased with the increase of FEOH, which was benefit to the micro-phase seperation.     

聚酯－ 聚醚复合型水性聚氨酯的制备与性能

以聚碳酸酯二元醇和聚醚二元醇为软段,异佛尔酮二异氰酸酯、扩链剂2,2 － 二羟甲基丙酸( DMPA) 及1,4 －丁二醇为硬段,用预聚法制备了稳定的阴离子型水性聚氨酯乳液及其胶膜,用红外光谱对其结构进行了表征,并研究了DMPA 用量和n( —NCO) /n( —OH) 对聚氨酯乳液稳定性及胶膜性能的影响。结果表明,聚酯－聚醚复合型水性聚氨酯胶膜具有优异的耐水性;在聚酯二元醇与聚醚二元醇的质量比为1 /1 的情况下,当DMPA 质量分数为6%、n( —NCO) /n( —OH) 为1. 3 时水性聚氨酯乳液及其胶膜的综合性能较好。     

碳纳米管聚氨酯复合材料的制备及其性能研究

将多壁碳纳米管超声分散后,利用直接共混法将分散液与水性聚氨酯混合,使其在平板上流延并烘干成膜,通过扫描电子显微镜(SEM)和X-射线衍射仪(XRD)对该材料的结构和性能进行表征,测定其透光率及抗张强度等,对该材料的性能进行了系统的研究.研究结果表明碳纳米管能够在聚氨酯中分散开,且碳纳米管能够很好的实现对聚氨酯的增强和增韧.     

聚氨酯/水滑石复合材料的制备及性能研究

以水滑石(LDH)和聚氨酯(PU)为原料,采用溶液流延法成膜,制备了一系列不同LDH含量的复合材料;借助广角X射线衍射和扫描电镜对PU/LDH复合材料的结构和形貌进行了表征,并对其热稳定性能和力学性能进行了测试。结果表明:LDH在PU基体中以插层结构为主,PU大分子链部分插入LDH层间;适量的LDH粒子能够均匀分散在PU基体中;LDH对PU材料的热分解无阻隔作用;适量的LDH粒子能有效提高PU材料的拉伸强度和断裂伸长率,当PU/LDH复合材料中LDH的质量分数为5%时,复合材料的拉伸强度和断裂伸长率达到最大,分别为15.9 MPa和443.8%。     

锂基水性聚氨酯的制备及其性能研究

以氢氧化锂(Li OH)为中和剂合成了一系列锂基芳香族聚醚型水性聚氨酯。红外光谱分析了水性聚氨酯结构;并探讨了不同二羟甲基丙酸(DMPA)含量对乳液电导率、粒径及胶膜DSC、力学性能的影响。结果表明,随着DMPA含量增加,乳液粒径减小,电导率增加;胶膜的软段Tg下降,拉伸强度增加,断裂伸长率减小;当DMPA含量为8.79%时,胶膜拉伸强度和乳液电导率均达到最大值,分别为35.38 MPa和1.580×10~(-3)S/cm。     

Preparation and properties of the main-chain-fluorinated thermoplastic polyurethane elastomer

A series of main-chain-fluorinated thermoplastic polyurethane elastomers (FTPU) based on fluoropoly(oxyalky1ene)diol (FPOA) were prepared by a one-step bulk polymerization. Polybutylene adipate (PBA) was combined with FPOA as a soft-segment in order to improve the solvent solubility of FTPU. The effects of the mass ratio of FPOA/PBA and the mass fraction of hard-segment on the mechanical properties of FTPU were investigated. The structure and morphology of FTPU were characterized by FTIR, GPC, DMA, surface property, and AFM analysis. The results indicated that the tensile strength and elongation at break for the sample of FTPU with FPOA/PBA ratio 30/70 can reach as high as 36.6 MPa and 1228.1%, respectively. It exhibited relatively high molecular weight, high damping property, enhanced thermal stability, and extremely low surface tension. The introduction of fluorinated blocks made the extent of incompatibility of the two phases of FTPU greater and the trend of micro-phase separation more serious.     

反应型聚氨酯热熔胶制备及其性能研究

以MDI(二苯基甲烷二异氰酸酯)和不同的低聚物二醇合成了反应型聚氨酯热熔胶,探讨了NCO质量分数、低聚物二醇种类、催化剂用量以及增黏树脂种类对聚氨酯热熔胶性能的影响。研究结果表明:随着NCO质量分数的增加,聚氨酯热熔胶的黏度下降、开放时间缩短、初粘力增大及终粘力先增大后减小,以NCO质量分数为1.6%时较佳;随着低聚物二醇结晶性增强,聚氨酯热熔胶的黏度增大、开放时间缩短、初粘力和终粘力增大;随着催化剂加入及用量的增加,热熔胶的开放时间缩短、终粘力上升速度加快、但初粘力基本不受影响;当催化剂的用量超过0.10%时,施胶经过相同的时间,其粘接强度并无明显区别;增黏树脂的加入,会增大聚氨酯热熔胶的黏度以及粘接力,缩短其开放时间,尤以萜烯酚醛树脂对于粘接力的改善效果最为明显,与聚氨酯热熔胶的相容性也最好。     

蓖麻油改性聚醚型水性聚氨酯乳液的性能

以聚醚、甲苯二异氰酸酯(TDI)、一缩二乙二醇、蓖麻油为主要原料,二羟甲基丙酸(DMPA)为亲水扩链剂,三乙胺为中和剂制备了稳定的阴离子水性聚氨酯乳液(WPU),研究了NCO/OH摩尔比、DMPA及蓖麻油的加入量对WPU的耐水性、稳定性和力学性能的影响,结果表明:改性后的乳液具有较好的稳定性,适量的蓖麻油可提高胶膜的拉伸强度及耐水性。当聚醚与蓖麻油质量比为7︰3、DMPA为5%、NCO与OH摩尔比为1.3时,WPU综合性能最好。     

Preparation and properties of microencapsulated octadecane with waterborne polyurethane

A series of microencapsulated blends of waterborne polyurethane (WBPU) as a matrix polymer and phase change material octadecane as a domain material were prepared in the presence of emulsifier. Nylon fabrics were coated with the coating materials formulated from microencapsulated blends, thickener, and hardener. The morphology and thermal behaviors of microencapsulated octadecane and WBPU/octadecane‐coated nylon fabrics were investigated using SEM, DSC, and KES‐F7. The size of octadecane microspheres increased with increasing octadecane contents. However, the size of microcsphere (1–6 μm) decreased with increasing emulsifier contents. ΔH_fusion, ΔH_{crystallization}, and their filling efficiencies of octadecane in film samples were found to increase with increasing microencapsulated blends, thickener, and hardener contents. Especially, thickener and hardener could function in trapping microencapsulated octadecane. Thermal characteristic Q_max (J/cm² s) values of WBPU/octadecane‐coated nylon fabrics are much higher than those of the control nylon fabric and WBPU‐coated nylon fabrics, indicating that the nylon fabrics coated with WBPU/octadecane blends have cooler touch sensation compared with nylon fabrics and WBPU‐coated nylon fabrics. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1596–1604, 2005     

松香基荧光水性聚氨酯的制备及性能

以异佛尔酮二异氰酸酯（IPDI）、丙烯酸松香加成物与甲基丙烯酸2-羟乙酯酯化物（RAG）为原料,二羟甲基丙酸（DMPA）为亲水扩链剂,5,7-二羟基-4-甲基香豆素（DHMC）为荧光扩链剂,成功制备了稳定性好的松香基荧光水性聚氨酯乳液（FWPU）。采用核磁共振氢谱、红外光谱、紫外光谱等对FWPU进行了结构表征,探讨了DHMC用量、猝灭剂1,4-对苯二酚（HQ）对FWPU荧光性能的影响,测试了聚氨酯膜的紫外防护性能。结果表明,DHMC成功接枝到聚氨酯主链上,随着其用量的增加,FWPU的荧光强度逐渐增大,用量为1%时荧光强度最大（达5002）;相比于DHMC,FWPU的荧光强度明显增大;HQ对FWPU荧光猝灭效果明显。加入DHMC,聚氨酯的紫外线防护系数从6.86增加到12.27,紫外防护性能得到改善,耐水性也有一定的提高。     

水性聚氨酯鞋用胶的制备及性能

以六亚甲基二异氰酸酯(HDI)、异佛尔酮二异氰酸酯(IPDI)、聚己二酸丁二醇酯二醇(PBA)和二羟甲基丁酸(DMBA)为主要原料,合成了水性聚氨酯(WPU)鞋用胶。研究结果表明:当R=[n(—NCO)︰n(—OH)]=(1.2~1.4)︰1、w(DMBA)=1.0%(相对于WPU鞋用胶质量而言)时,合成的WPU鞋用胶之综合性能相对最好,其固含量较高、初始黏度较大、吸水率较低、剥离强度较高且储存稳定性较好。     

三维石墨烯/聚氨酯复合材料的制备与特性

以氧化石墨烯(GO)为网络骨架的前驱体,通过水热还原、冷冻干燥制备了石墨烯气凝胶(GA);再以聚氨酯(PU)为复合材料的填充体,调节PU软硬度与流动性并真空浸渍气凝胶GA,两步法制备出互咬型三维石墨烯/聚氨酯(3DGP)复合材料。利用SEM、Raman、FTIR对GO、GA、3DGP的结构与形貌进行了表征,并采用TGA-DSC和自制压阻测试平台分析热稳定性和压阻特性。结果表明:6 g/L GO水溶液在还原剂乙二胺(EDA)作用下,GO片层间相互连接形成规整蜂窝状三维网络结构,其孔径约0.8mm,3DGP中PU与GA能很好地咬合;三维网络骨架的连续性为热运输载体声子提供了良好通道,使得3DGP热稳定性能显著提升,失重率5%时温度较PU提升了45℃;具有低迟滞性(8.7%)并且在压阻测量区间表现出两种压阻效应。     

磁性纳米颗粒去除饮用水中铬和镉离子性能的初步研究

基于表面修饰的四氧化三铁磁性纳米材料具有高比表面积、高吸附能力及吸附速度快等优点。研究了Fe_3O_4磁性纳米材料的制备及表面修饰条件,及其对饮用水中微量铬和镉离子的吸附、脱附性能。结果表明,在氨水浓度为0.5 mol/L时,采用化学共沉淀法制备的四氧化三铁磁性纳米颗粒产率最大;十二烷基磺酸钠浓度为300 mg/L,与四氧化三铁磁性纳米颗粒配比为2∶3,溶液pH为5.0,表面修饰的四氧化三铁磁性纳米颗粒对重金属镉和铬离子有显著的去除能力,对镉和铬离子的饱和吸附量分别为3.09,2.11 mg/g,在pH为7时,其对镉和铬离子的解析率分别为79%,60.5%。所制备材料的平衡吸附量与平衡质量浓度之间符合Langmuir和Freundlich等温吸附方程。