二氧化双环戊二烯环氧树脂/聚氨酯互穿聚合物网络的制备及其性能

以N-对羧基苯基马来酰亚胺(CPMI)和乙二醇单双环戊二烯基醚(EMDCPE)为单体合成了新型共聚物(CPMI-co-EMDCPE),将其作为二氧化双环戊二烯环氧树脂(DCPDE)/聚氨酯(PU)互穿聚合物网络(IPNs)体系的固化剂,以期改善互穿聚合物网络之间的相容性和热性能.采用红外光谱法对固化剂及互穿聚合物网络的结构进行表征.对不同固化体系涂膜的热稳定性、力学性能和微观形貌进行了研究.研究表明,互穿聚合物网络的形成,提高了二氧化双环戊二烯环氧树脂的弯曲强度、附着力和抗冲击强度.新型固化剂的加入普遍提高了二氧化双环戊二烯环氧树脂/聚氨酯互穿聚合物网络的耐热性能,增韧改性后的环氧树脂呈现明显的两相结构.     

壳聚糖基Semi-IPN多孔膜的制备及其吸附性能的研究

利用戊二醛在成膜时使壳聚糖交联,形成壳聚糖／聚乙二醇半互穿网络,进一步抽提制得壳聚糖基多孔膜。多孔膜在溶液中有较好的化学稳定性,孔径尺寸在亚微米级别,可以通过改变交联剂用量得到不同孔结构的多孔膜。多孔膜对甲基橙和活性橙82有较好的吸附性,染料分子的极性基团越多,壳聚糖基多孔膜对其吸附能力越强。     

药物缓释材料的合成与性能

研究了聚氨酯/聚醚半互穿网络聚合物的合成、溶胀行为和释放性能,特别是疏水组成、线型聚醚结构和温度对网络的溶胀平衡和溶胀动力学的影响。同时还测量了大分子肝素在填充时的分配系数和释放速度,并对肝素从溶胀的互穿网络聚合物中释放的机理进行了讨论。     

药和缓释材料的合成与性能

研究了聚氨酯／聚醚半互穿网络聚合物的合成、溶胀行为和释放性能，特别是疏水组成、线型聚醚结构和温度对网络的溶胀平衡和溶胀动力学的影响。同时还测量了大分子肝素在填充时的分配系数和释放速度，并对肝素从溶胀的互穿网络聚合物中释放的机理进行了探讨。     

聚苯乙烯互穿聚合物网络研究进展

综述了聚苯乙烯互穿聚合物网络的研究进展,阐述了分步互穿聚合物网络、同步互穿聚合物网络、半互穿聚合物网络和胶乳互穿聚合物网络的制备方法,介绍了组成和制备方法对PS互穿聚合物网络的相态结构和互穿聚合物网络相容性的影响。阐述了PS互穿聚合物网络的组成和结构对于力学性能、热力学性能、流变性能、气体透过率和吸附性的影响,最后综述PS互穿聚合物网络存在的问题及发展趋势。     

固化动力学对PU/VER同步互穿网络聚合物性能的影响

互穿网络聚合物(IPNs)是一种特殊的交联聚合物合金.本研究以聚氨酯(PU)和乙烯基酯(VER)预聚物为原料,在室温下合成了互穿网络聚合物.采用傅立叶红外光谱法跟踪了网络形成的动力学过程并进行半定量分析,研究了固化体系对互穿纲络聚合物的摩擦学性能、力学性能及光学性能等的影响.结果显示,两种预聚物在固化过程中虽遵循不同的聚合机理,却相互影响制约.通过改变引发剂和催化剂的配比得到的样品显示出不同特性.当VER引发剂的用量为0.75%,PU催化剂的用量为0.6%时,两网络可基本实现同步互穿;同步互穿网络聚合物显示出良好的耐磨性,在实验条件下涂层寿命可达28.81 min,且力学性能优异,在可见光波长范围内具有良好的透光性, 450 nm处的透光率可达85%.     

二氧化双环戊二烯环氧树脂/聚氨酯互穿聚合物网络的制备与性能研究

制备了新型二氧化双环戊二烯环氧树脂(DCPDE)/聚氨酯(PU)互穿聚合物网络(DCPDE/PU IPNs).采用红外光谱法对互穿聚合物网络的结构进行了表征.对不同固化体系的热稳定性、力学性能和涂膜的微观形貌进行了研究.研究结果表明:互穿聚合物网络的形成,提高了二氧化双环戊二烯环氧树脂的弯曲强度、附着力和耐冲击性.固化剂的加入改进了聚氨酯/环氧树脂互穿网络的耐热性能.增韧改性后的环氧树脂比改性之前的环氧树脂呈现明显的两相结构.     

基于微相分离型低表面能防污材料的研制

以端羟基聚丁二烯HTPB,TDI为原料制得端异氰酸酯基聚氨酯预聚体,再与环氧树脂E-51反应制得HTPB-TDI-EP部分互穿网络。通过红外光谱、接触角、动态力学分析、扫描电子显微镜对聚合物体系的结构与性能进行研究和表征。实验结果表明,以聚氨酯为连续相,环氧树脂为分散相形成的互穿网络聚合物TDI与HTPB形成网络比较致密,具有较强的耐水性能,表面疏水性增强,表面自由能降低,较单纯聚氨酯相比,微相分离的静态水接触角从73.8°提高到92.8°,具有一定的疏水性能。     

脂肪族聚碳酸酯型聚氨酯互穿网络聚合物的研究

简述了脂肪族聚碳酸酯聚氨酯（ＰＣＵ）互穿网络聚合物（ＩＰＮ）的发展及最新研究动态。介绍了其制备、表征、结构与性能的关系。预示了聚碳酸酯型聚氨酯互穿网络聚合物材料的开发前景。     

聚氨酯改性不饱和聚酯木器底漆的研究

为了提高不饱和聚酯木器底漆的低温打磨性,采用聚氨酯对不饱和聚酯进行改性,形成互穿聚合物网络(IPN)结构,通过IPN协同效应,结合聚氨酯涂料和不饱和聚酯涂料的优点,获得干燥速度快,易打磨,性能优异的漆膜,聚氨酯用量为30%～50%时效果最佳。     

Semi-interpenetrating polymer networks from castor oil-based polyurethanes and chlorinated rubber

Semi-interpenetrating polymer networks (semi-IPNs) were prepared by crosslinking castor oil in the presence of chlorinated rubber. Crosslinking in toluene solution was effected with 2,4-toluene diisocyanate or hexamethylene diisocyanate at various NCO/OH ratios. The semi-IPNs were obtained as tough films and were characterized by their mechanical, thermal, morphological and electrical properties.     

The role of branching architecture in shape memory semi-IPNs: Shape memory effect and tube model analysis

The impact of branching architecture of one continuous uncrosslinked phase on properties of classic shape memory semi-interpenetrating polymer networks (semi-IPNs) was explored. Crosslinked poly (methyl methacrylate) (PMMA)/star-shaped polyethylene glycol (PEG) (PMMA/SPEG) semi-IPNs and PMMA/linear PEG (PMMA/LPEG) semi-IPNs were synthesized with the same PEG content. Mechanical properties, phase structure, thermal properties, dynamic mechanical properties, and shape memory properties of these two semi-IPNs systems were compared. Due to the better compatibility of SPEG in the PMMA network, which was derived from little crystallization compared with PMMA/LPEG semi-IPNs, PMMA/SPEG semi-IPNs exhibited a combination of large tensile strength and high elongation at break. PMMA/SPEG semi-IPNs, which had little crystallization exhibited superior shape recovery versus PMMA/LPEG semi-IPNs, which had more crystallization. Moreover, the higher the crystallinity in PMMA/PEG semi-IPNs was the worse long-term temporary shape retention. Based on tube model theory, the high shape recovery capacity of PMMA/SPEG semi-IPNs is mainly ascribed to the retraction of free PEG arms, which is entropically favorable and thermally activated due to the fluctuations of the path length. This result is supported by stress relaxation analysis and the influence of long shape fixity time on shape fixity ratio for these two systems.     

Synthesis,properties, and permeation of solutes through hydrogels based on poly(ethylene glycol)-co-poly(lactones) diacrylate macromers and chitosan

Triblock copolymers from poly(ethylene glycol) (PEG) and D,L -lactide or ε-caprolactone were synthesized to prepare semi-interpenetrating polymer networks (semi-IPNs) with chitosan by ultraviolet (UV) irradiation method. Then, the solute permeation through these semi-IPNs hydrogels were investigated. The structures of semi-IPNs were confirmed by Fourier transform infrared (FTIR) spectroscopy and wide-angle X-ray diffractometer (WAXD). The equilibrium water content (EWC) of these hydrogels was in the range of 67–75%. The crystallinity, thermal properties, and mechanical properties of semi-IPNs hydrogels were studied. All the hydrogels revealed a remarkable decrease in crystallinity as compared with the PEG macromer itself. The tensile strengths of semi-IPNs hydrogels in a dry state were rather high, but those of hydrogels in a wet state decreased drastically. The permeabilities of solutes of hydrogels followed the swelling behaviors and were regulated by solute size. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2151–2158, 1999     

Investigation of the preparation and physical properties of a novel semi-interpenetrating polymer network based on epoxised NR and PVA using maleic acid as the crosslinking agent

Natural rubber (NR) and its derivatives as renewable and biodegradable materials have attracted considerable attention because of the serious pollution problems caused by synthetic materials and a shortage of resources. A new semi-interpenetrating polymer network (semi-IPN) based on epoxidised natural rubber and polyvinyl alcohol containing maleic acid as a crosslinking reagent was synthesized and characterized by FTIR, XRD, SEM, swelling ratio in both distilled water and toluene, and mechanical properties. The curing time and dose of maleic acid were varied from 10 to 60 min, and from 10 to 60% (w/w), respectively. An IR spectroscopic study indicated the presence of an ester linkage at 1730 cm⁻¹ in maleic acid crosslinked with PVA in semi-IPN films. In addition, the crystalline content of PVA dramatically decreased after adding maleic acid in the semi-IPN, as observed from its XRD. The semi-IPNs exhibit good mechanical properties, thermal stability, characteristics of a polyvinyl alcohol–maleic acid polymer network. An SEM of the semi-IPNs containing maleic acid showed no phase separation, when compared with the sample prepared in the absence of maleic acid.     

Three-dimensional macro/mesoporosity developments in polydimethylsiloxane

Macro/mesoporous polydimethylsiloxanes (PDMS) were prepared with the purpose of vascular grafts. Oligoester-containing semi-interpenetrating polymer networks (semi-IPNs) can be used as precursors for generation of networks with tunable pore sizes. Novel poly(methyl methacrylate)/PDMS semi-IPNs were prepared by varying structural parameters. Extraction of uncrosslinked oligoester subchains from semi-IPNs was investigated. To tailor the morphology of porous structure, influence of some factors including porogen type, different polymerization conditions, monomer type, and concentration, crosslinking agent concentration were studied. PDMS networks were examined by field emission scanning electron microscopy. A uniform porous structure with interconnected pores was detected in horizontal and vertical cross sections of PDMS.     

Properties and interfacial bonding of regenerated cellulose films coated with polyurethane–chitosan IPN coating

Water-resistant films were prepared by coating a castor oil-based polyurethane–chitosan (PU–CH), in which grafted interpenetrating polymer networks (IPNs) were produced, on a regenerated cellulose (RC) film. The tensile strengths of the coated films cured at 90°C for 5 min reached 853 kg cm⁻² (dry state) and 503 kg cm⁻² (wet state) and were obviously higher than those of the films of uncoated and coated with PU coating. Moreover, the coated films have excellent water resistivity, low vapor permeability, and good size stability, and their optical transmittance is even better than that of the RC film in the range of 400–800 nm. The interfacial structure of the coated films was investigated by using spectroscopy infrared, ultraviolet spectroscopy, transmission electron microscopy, and electron probe microanalysis. It was shown that the strong interfacial bonding with chemical and hydrogen bonds between the RC film and the coating exists. The PU prepolymer in the IPN coating penetrated through the interface into the RC film and partly crosslinked with the cellulose, forming a semi-IPNs. The chitosan in the PU–CH coating plays an important role not only in accelerating the cure of the coating but also in improving the mechanical properties and biodegradability of the coated film. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1313–1319, 1998     

Morphology and mechanical properties of styrene-butadiene-styrene/polystyrene semi-interpenetrating polymer networks and their blends

SBS/PS semi-interpenetrating polymer networks (semi-IPNS) were synthesized by swelling a linear styrene-butadiene-styrene (SBS) triblock copolymer (SBS, Kraton 1102) with styrene monomer plus benzoin as photoinitiator and divinylbenzene as cross-linking agent. Polyblends were prepared by solution casting of SBS and polystyrene (PS) in their ideal solvents. Measurements were made for viscoelastic properties and mechanical properties of phase-separated polymer alloy (including SBS copolymers Kraton 4122), semi-IPNs and polyblends of several SBS and PS, with the same total PS content (48% PS). The dynamic mechanical behaviour shows distinct transitions for each polymer, in agreement with electron microscopy results that SBS/PS polymer alloy forms two phases; however, the phase domains were finer in the semi-IPNs than in SBS triblock copolymer and in polyblends of the corresponding polymers. Stress-strain data show that semi-IPNs exhibit higher tensile strength and modulus than the other two corresponding polymer alloys. A master curve was plotted to illustrate the stress relaxation behaviour of samples at higher temperatures. Our results also reveal that semi-IPNs have much better high-temperature mechanical strength.     

A study of epoxy resin–acrylated polyurethane semi-interpenetrating polymer networks

Epoxy resin–acrylated polyurethane semi-interpenetrating polymer networks (semi-IPNs) were synthesized containing various ratios of the diglycidyl ether of bisphenol-A (DGEBA)-based epoxy resin and an acrylated aliphatic urethane oligomer. The synthesis was carried out in the presence of a mixture of triarylsulfonium hexafluoroantimonate salts as a dual photoinitiator that initiates both the cationic polymerization of the epoxy resin and the free-radical polymerization of the acrylated urethane oligomer simultaneously, upon irradiation with ultraviolet light. The simultaneous photopolymerization, followed by isothermal differential scanning calorimetry measurements, gave rise to simultaneous semi-interpenetrating polymer networks (semi-SINs). During polymerization, partial inhibition of the cationic polymerization was noticed. This was investigated by determination of the gel content and the infrared spectroscopy of the soluble fraction, after extraction of the synthesized polymer films in a Soxhlet apparatus, and by determination of the network density of investigated systems with thermal mechanical analysis. The compatibility of the components in the semi-IPNs was investigated by dynamic mechanical thermal analysis. It was found that glass transition temperatures are shifted inwardly, which indicated that the epoxy resin–acrylated polyurethane semi-IPNs were compatible. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:111–119, 1998     

Thermal effects in poly(hexamethylene adipamide) and polyoxymethylene at high hydrostatic pressures

The dynamic mechanical properties, transition behavior, and morphology of polycarbonate (PC)-polyurethane (PU) semi-interpenetrating polymer networks (semi-IPNs) and linear blends were studied by means of Rheovibron, differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). Two glass transition temperatures corresponding to polycarbonate and polyurethane were observed and microphase separation was further evident with TEM. In PC/PU semi-IPNs, two glass transition temperatures were shifted inwardly indicating that the interpenetrating network of polyurethane increases the mutual miscibility of PC and PU. The average phase domain was 500Å in semi-IPNs and the phase domains were in the range 1000–6000 Å in linear blends of the corresponding polymers. The compatibilities of PC and PU were greatly influenced by the molecular weight of polyols in PU prepolymer and the ratio of NCO/OH; lower molecular weight polyols and higher NCO/OH ratio resulted in better compatibility, and finer phase domains in PC and PU linear blends and semi-IPNs.     

Damping materials based on polyurethane/polyacrylate IPNs: dynamic mechanical spectroscopy,mechanical properties and multiphase morphology

Four kinds of polyurethane/polyacrylate interpenetrating polymer networks (crosslinked polyacrylate semi-IPNs, crosslinked polyurethane semi-IPNs, all-IPNs and all-IPNs with opposite charge groups) were synthesized by a simultaneous polymerization process. Their damping properties, mechanical properties and multiphase morphology were investigated by automatic torsional braid analysis, an Instron tester, small-angle X-ray scattering (SAXS) and tranmission electron microscopy (TEM). The results show that the attraction between positively charged groups and negatively charged groups improved the miscibility of the two components. When the weight ratio of polyurethane/polyacrylate was 1:2, the resulting IPN materials possessed better damping and mechanical properties, and the specific surface area reached a maximum. © 1999 Society of Chemical Industry