Synthesis and characterization of fluorinated polyacrylate–cellulose acetate butyrate interpenetrating polymer networks

Fluorinated polyacrylates are highly hydrophobic and oleophobic. However, their poor mechanical properties prevent their development in many applications. Combination of a fluorinated polyacrylate network with a rigid cellulose acetate butyrate (CAB) network in an interpenetrating polymer network (IPN) architecture is an effective method for improving the mechanical properties of fluorinated polyacrylates. IPNs combining poly(3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl acrylate) (polyAcRf6) with CAB were prepared according to an in situ polymerization/crosslinking synthesis. CAB was crosslinked by addition between unmodified hydroxyl groups and the isocyanate of a pluri‐isocyanate crosslinker. The fluorinated network was obtained through free‐radical copolymerization of 3,3,4,4,5,5,6,6,7,7,8,8,8‐tridecafluorooctyl acrylate with poly(ethylene glycol dimethacrylate). The rates of formation of both networks were followed using Fourier transform infrared spectroscopy. Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) of IPNs show a single glass transition temperature and a single mechanical relaxation temperature, which are characteristic of a high degree of interpenetration between the partner networks. The mechanical properties of IPNs are greatly improved compared with those of the single fluorinated network. CAB/polyAcRf6 IPNs were prepared, and characterized using DSC and DMTA as well as contact angle measurements for their surface properties. As hoped, the mechanical properties of such materials are much improved compared with those of the fluorinated partner alone. Copyright © 2010 Society of Chemical Industry     

宽温域高阻尼互穿聚合物网络材料的结构与性能

以环氧丙烯酸酯和甲基丙烯酸丁酯(二者质量比为2/1)混合物为乙烯基酯树脂(VER)。1,4-丁二醇为扩链荆,采用“同步互穿”工艺,室温下与聚氨酯(PU)预聚物固化制备了低温至室温区阻尼温域近70℃、损耗因子(tanδ)大于0．4的PU/VER互穿聚合物网络(IPN)。结果表明,当PU/VER(质量比,下同)为70/30时,IPN的tanδ大于0.7的阻尼温域近40℃。采用傅里叶变换红外光谱仪及原子力显微镜考察了试样的连续相构成及微观结构表明,形成的双相连续“同步互穿”体系的相畴尺寸在纳米级范围,组成比为70/30的IPN较50/50者相容性好。力学性能测试结果表明,随VER用量的增加．试样具有由弹性到脆性的形变规律。     

丙烯酸酯系胶乳互穿聚合物网络的合成及阻尼性能

以种子乳液聚合法合成了聚苯乙烯／聚丙烯酸乙酯、聚甲基丙烯酸乙酯／聚丙烯酸丁酯的核-壳胶乳互穿聚合物网络(LIPN),分别测试了不同配比LIPN及其共混物的阻尼性能、物理机械性能和吸水性能。结果表明,LIPN共混物是具有阻尼温域宽、阻尼性能优、物理机械性能良好和吸水率较低的阻尼材料,其阻尼性能主要取决于共混组分的性能、配比和内耗能的贡献,并且与共混物的织态结构也密切相关。     

Mechanical properties of blocked polyurethane/epoxy interpenetrating polymer networks

The mechanical properties of blocked polyurethane(PU)/epoxy interpenetrating polymer networks (IPNs) were studied by means of their static and damping properties. The studies of static mechanical properties of IPNs are based on tensile properties, flexural properties, hardness, and impact method. Results show that the tensile strength, flexural strength, tensile modulus, flexural modulus, and hardness of IPNs decreased with increase in blocked PU content. The impact strength of IPNs increased with increase in blocked PU content. It shows that the tensile strength, flexural strength, tensile modulus, and flexural modulus of IPNs increased with filler (CaCO₃) content to a maximum value at 5, 10, 20, and 25 phr, respectively, and then decreased. The higher the filler content, the greater the hardness of IPNs and the lower the notched Izod impact strength of IPNs. The glass transition temperatures (T_g) of IPNs were shifted inwardly compared with those of blocked PU and epoxy, which indicated that the blocked PU/epoxy IPNs showed excellent compatibility. Meanwhile, the T_g was shifted to a higher temperature with increasing filler (CaCO₃) content. The dynamic storage modulus (E′) of IPNs increased with increase in epoxy and filler content. The higher the blocked PU content, the greater the swelling ratio of IPNs and the lower the density of IPNs. The higher the filler (CaCO₃) content, the greater the density of IPNs, and the lower the swelling ratio of IPNs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1826–1832, 2006     

Correlation between mechanical damping and interphase content in interpenetrating polymer networks

Recently, some interpenetrating polymer networks with good mechanical damping properties have been synthesized. However, the effect of morphology on this property has not yet been clearly elucidated. Herein, two polystyrene–polyurethane interpenetrating polymer networks, which were grafted using TMI [benzene‐1‐(1‐isocyanato‐1‐methyl ethyl)‐3‐(1‐methylenyl)] and HEMA (2‐hydroxyethyl methacrylate), respectively, have been investigated, as model samples, by modulated‐temperature differential scanning calorimetry and by dynamical mechanical thermal analysis. The results indicate that there is a correlation between mechanical damping and both interphase content and the distribution of composition in the interphase region. The findings should provide valuable information for the design of future damping materials. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2439–2442, 2001     

Spin probe study of semi‐interpenetrating polymer networks based on polyurethane and polymethacrylate functional prepolymers

The motional transition and heterogeneity of semi‐interpenetrating networks (SIPNs) based on polyurethane (PU) with carboxylic groups and methacrylic copolymer (PM) with tertiary amine groups were studied by the electron spin resonance (ESR) spin probe method. The concentration of functional groups in both prepolymers varied from 0 to 0.45 mmol g^?1. Spin‐probed SIPNs show that the temperature‐dependent spectra are sensitive to polymer interactions imposed by functional groups. These interactions determine the free volume distribution in the matrix and temperature at which motional transition takes place. The fraction of free volume increases with functional group concentration and reaches its maximum at 0.25 mmol g^?1. Further increases in the functional group concentration reduce the free volume. The results of the networks with strong interactions are discussed in terms of the interference of the plasticizing effect of the PU component and the formation of possible cluster cross‐links, which restricts segmental motions. Copyright © 2003 Society of Chemical Industry     

Synthesis and mechanical properties of leather–epoxy interpenetrating polymer networks

Leather–epoxy interpenetrating polymer networks (IPNs) were synthesized; these IPNs have an approximate epoxy concentration of 25 wt %. The flexural and tensile moduli of the IPNs prepared are equivalent to those of the epoxy resin. The Izod impact energy and fracture toughness measured for the IPNs, however, exceed those attained by the epoxy resin alone by at least a factor of 4. The glass transition of leather–epoxy IPNs occurs over a wide temperature range, thus indicating that the IPN is an intimate admixture of the epoxy resin throughout the collagen matrix of the hide. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1224–1232, 2000     

Synthesis and characterization of sequential interpenetrating polymer networks of novolac resin and poly(ethyl acrylate)

Interpenetrating polymer networks (IPN) of Novolac/poly(ethyl acrylate) have been prepared via in situ sequential technique of IPN formation. Both full and semi IPNs were characterized with respect to their mechanical properties that is, ultimate tensile strength (UTS), percentage elongation at break, modulus, and toughness. Physical properties of these were evaluated in terms of hardness, specific gravity, and crosslink density. Thermal behavior was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The morphological features were observed by an optical microscope. There was a gradual decrease in modulus and UTS, with consequent increases in elongation at break and toughness for both types of IPNs with increasing proportions of PEA. An inward shift and lowering (with respect to pure phenolic resin) of the glass transition temperatures of the IPNs with increasing proportions of PEA were observed, thus, indicating a plasticizing influence of PEA on the rigid, brittle, and hard matrix of crosslinked phenolic resin. The TGA thermograms exhibit two‐step degradation patterns. An apparent increase in thermal stability at the initial stages, particularly, at lower temperature regions, was followed by a substantial decrease in thermal stability at the higher temperature region under study. As expected, a gradual decrease in specific gravity and hardness values was observed with increase in PEA incorporation in the IPNs. A steady decrease in crosslink densities with increase in PEA incorporation was quite evident. The surface morphology as revealed by optical microscope clearly indicates two‐phase structures in all the full and semi IPNs, irrespective of acrylic content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

互穿聚合物网络阻尼材料研究进展

介绍了互穿聚合物网络阻尼材料的研究进展，讨论了对其阻尼性能的评价以及组分、组分间的相容性、交联密度、无机填料等影响性能的因素，并展望了互穿聚合物网络的研究前景。     

具有良好阻尼性能的蓖麻油互穿网络弹性体

由蓖麻油、甲苯二异氰酸酯(TDI)、单端羟基(甲基)丙烯酸酯预聚物及/或(甲基)丙烯酸酯单体出发,在二丁基二月桂酸锡及氧化还原引发剂存在下合成了四种接枝型互穿网络聚合物(IPN)。研究了产物的力学性能及动态力学性质。结果表明,某些接枝IPN,例如蓖麻油/TDI/单端羟基甲基丙烯酸丁酯预聚物/单端羟基丙烯酸丁酯预聚物组成的IPN,蓖麻油/TDI/丙烯酸丁酯单体/单端羟基甲基丙烯酸乙酯预聚物组成的IPN及蓖麻油/TDI/甲基丙烯酸乙酯单体/单端羟基甲基丙烯酯丁酯预聚物组成的IPN均呈现突出的阻尼行为,tanδ>0.3的温度范围很广,而且最大的tanδ大于1.1。这些IPN呈现良好的橡胶样力学性能。     

氟树脂/聚丙烯酸酯胶乳型互穿网络的合成

采用原位聚合和互穿网络的方法,以氟树脂乳液作种子乳液,氟碳乳化剂和碳氢乳化剂为复配乳化剂,合成了聚丙烯酸酯和氟树脂胶乳型互穿网络聚合物(LIPN),所合成的乳液稳定性良好。通过对聚合物的微观形态、动态机械力学性能和接触角的分析,表明用此方法乳液聚合,可以较好地改善两种树脂的相容性,聚合物的表面能有了较大的下降。     

互穿聚合物网络研究进展

综述了互穿聚合物网络（ＩＰＮ）研究的进展，介绍了ＩＰＮ在体系，表征，应用等方面的新动向。     

Filler effect on formation and properties of interpenetrating polymer networks based on polyurethane and polyesteracrylate

The formation processes of unfilled and filled interpenetrating polymer networks (IPNs) and some of their physico-mechanical properties have been investigated. The IPN formation kinetics and the constituent network curing rates determine the rate and degree of microphase separation. This in turn determines the boundary layer composition and structure. Introduction of filler into the IPN during formation affects greatly the crosslinking reaction and the microphase segregation of homopolymers. It has been shown that the degree of phase segregation in filled IPNs differs from that in unfilled ones. All the fillers were found to shorten the time of internal stress appearance and to increase its value for IPNs with predominantly high-modulus component content. Some filled IPNs were shown to have greater thermodynamic stability than unfilled ones.     

Effect of physical ageing on the viscoelasticity of interpenetrating polymer networks

The effect of physical ageing on viscoelastic properties was studied for semi‐IPNs based on crosslinked polyurethane and poly(butyl methacrylate) taken in the ratio 75/25 by mass. The viscoelastic properties of IPNs were studied after physical ageing and after heat treatment at 60 °C. Significant changes in viscoelastic behaviour after ageing were observed. It was found that heterogeneous systems such as IPNs have their own specific features of physical ageing which are related to the existence of two glass transition to temperatures. Relaxation processes to establish the equilibrium state may need a long period of time. © 2000 Society of Chemical Industry     

Synthesis and properties of elastomer‐modified epoxy–methacrylate sequential interpenetrating networks

The structure and properties of copolymerized sequential‐interpenetrating networks (SeqIPNs) synthesized from amine‐cured epoxies and free‐radical polymerized dimethacrylates were examined. Materials were synthesized with and without the incorporation of an epoxy‐terminated butadiene–nitrile reactive elastomer. Synthesis proceeded through full thermal cure of the epoxy–amine network, followed by polymerization of the methacrylate network. The methacrylate reactions were free‐radically induced using thermal (peroxide‐initiated) or photochemical [electron‐beam (e‐beam)] techniques. Fourier transform infrared spectroscopy was used to monitor epoxy–amine step‐growth polymerization in situ and to measure final cure conversion of methacrylates. Structural examination of the IPNs using atomic force microscopy and scanning electron microscopy revealed microphase separation in the neat–SeqIPN materials and macroscopic phase separation of rubber‐rich domains for elastomer‐modified networks. Dynamic mechanical analysis of the SeqIPN determined that the properties of the network are strongly dependent on the cure conditions. Furthermore, the viscoelastic behavior of the e‐beam–cured SeqIPN could be adequately described by the Williams–Landel–Ferry and Kohrausch–Willams–Watts equations, presumably because of a strong coupling between the epoxy–amine and methacrylate networks. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 530–545, 2001     

Property evaluation and structure analysis of polyurethane/epoxy graft interpenetrating polymer networks

Polyurethanes obtained from 4,4′‐diphenylmethane diisocyanate (MDI) and polydiols with different molecular weights (polyethylene glycol and polyoxypropylene diols) were used as modifiers for diglycidyl ether of bisphenol A. Impact strength (IS), critical stress intensity factor (K_C), flexural strength and flexural strain at break were measured as a function of polyurethane (PUR) type and content. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and infrared spectroscopy (FTIR) were employed for the structure and morphology analysis. It was found that the addition of polyurethane with an excess of isocyanate groups to epoxy resin resulted in the formation of a grafted interpenetrating polymer network structure. The mechanical properties of epoxy resin were improved with 5 and 10% PUR. Moreover, it was observed that composites containing PUR based on higher molecular weight (PUR 1002 and PUR 2002) with long flexible segments exhibited higher impact strength while PUR prepared from polyethylene glycol had a higher flexural energy to break and a higher flexural modulus. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

SBS/P(St-MMA)热塑性互穿聚合物网络结构与力学性能

采用原子转移自由基聚合(ATRP)法合成了苯乙烯一甲基丙烯酸甲酯共聚物[P(St-MMA)]。采用分步法制备了SBS／P(St-MMA)热塑性互穿聚合物网络(TIPN)。研究了P(St-MMA)质量分数、MMA／St(摩尔比,下同)和不同聚合方式对TIPN结构和力学性能的影响。结果表明：生成了具有较窄相对分子质量分布的P(St-MMA);P(St-MMA)质量分数在30％,左右时,采用ATRP法制备的SBS／P(St-MMA)TIPN拉伸强度和扯断伸长率达到最大;随MMA／St增加,TIPN拉伸强度增大,扯断伸长率不变。常规自由基聚合法制备的TIPN与ATRP法相比,前者相对分子质量高,相对分子质量分布宽,拉伸强度高,扯断伸长率随P(St-MMA)质量分数增加而下降。     

Static and dynamic mechanical properties of modified bismaleimide and cyanate ester interpenetrating polymer networks

Interpenetrating polymer networks (IPNs) based on different ratios of modified bismaleimide (BMI) resin [BMI/2,2′‐diallylbisphenol A (DBA)] and cyanate ester (CE) (b10) have been synthesized via prepolymerization followed by thermal curing. A systematic study of both static and dynamic mechanical properties of the cured BMI/DBA–CE IPN resin systems was conducted through flexural, impact testing, and dynamic mechanical analysis (DMA). The static mechanical investigation shows that the flexural strength, flexural strain at break, and impact strength of the cured BMI/DBA–CE IPN resin systems are relatively lower than that calculated by rule of mixture of two individuals: BMI/DBA and b10. However, the flexural moduli of the IPN resin systems have more consistent features compared to that calculated by rule of mixture. Single damping peaks are detected for the cured BMI/DBA–CE IPN resin systems, which suggests a substantial degree of interpenetration between two networks. The damping peaks of the cured BMI/DBA–CE IPN resin systems do tend to become broader with increasing concentration of BMI/DBA, whereas the intensity of damping peaks of the IPN resin systems decreases. The obtained results not only provide insight information about the characteristic structures of these BMI/DBA‐–CE IPN resin systems, but also give guidelines for their applications. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2000–2006, 2003     

Uralkyd and poly (butyl methacrylate) interpenetrating polymer networks

ABSTRACT:: Hydroxyl terminated alkyds synthesized from castor oil, glycerol, and different dibasic acids were used to develop uralkyds and their interpenetrating polymer networks (IPNs) with polybutyl methacrylate (PBMA). Glass transition temperature measurements gave the evidence of interpenetration. The IPNs were characterized for their physicomechanical properties and their phase morphology was studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). As the concentration of the uralkyd in IPNs increases, a gradual increase in elongation, density, and swelling with a consequent decrease in the hardness were observed for all IPNs. Swelling is relatively more prominent in methyl ethyl ketone (MEK) and toluene than in water. From SEM it was observed that IPNs of PBMA‐uralkyd containing phthalic anhydride (UA‐P) as an acid part showed greater compatibility than those containing dimethyl terephthalate (UA‐D). From thermogravimetric analysis (TGA) no significant change was observed in the degradation behavior of the IPNs. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 825–832, 2000