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。     

The application of bulk polymerized acrylic and methacrylic interpenetrating polymer networks to noise and vibration damping

Novel acrylic/methacrylic interpenetrating polymer networks (IPNs) were examined by dynamic mechanical spectroscopy for their damping capabilities. While simple homopolymers exhibit high damping properties only over a 20–30°C range, multicomponent polymer systems with controlled degree of miscibility, such as IPNs, may exhibit high damping properties over temperature ranges as broad as approximately 100°C. Two series of IPNs based on poly(n-butyl acrylate) and poly(n-butyl methacrylate) were synthesized and the dynamic mechanical properties were investigated using a Rheovibron. Graphite was incorporated into the poly(n-butyl acrylate) homopolymer and a few IPNs to measure the change in the damping properties. For important IPN compositions, tan δ values between 0.4 and 0.85 were observed over a 75°C plus temperature range. Graphite increased the damping properties of poly(n-butyl acrylate) and the IPNs, as indicated by the tan δ values.     

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。     

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     

Structure and damping properties of polydimethylsiloxane and polymethacrylate sequential interpenetrating polymer networks

By using the technology of the sequential interpenetrating polymer network, a series of novel damping materials based on a polydimethylsiloxane (PDMS)/polyacrylate (PAC) matrix with polymethacrylate (PMAC) were synthesized. They have a controllable broad transition peak spanning the temperature range of 150–220°C and the medial value of loss factor with maximum of 0.35–0.60. Dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and atomic force microscopy (AFM) were applied to analyze and characterize the transition behavior and the microphase structure of the materials. It was found that the size and height of a transition peak at both the low‐ and the high‐temperature zones change as a function not only of the concentration of PMAC and PDMS but also of the kind of PMAC; simultaneously, the low‐ temperature behavior was also governed by the crystallization of PDMS. The content of the crosslinking agent exerts a significant influence on the configuration of the curves of the transition peaks. AFM shows a characteristic phase morphology of double‐phase continuity containing a transition layer and domain less than 1 μm, indicating that the interwoven multilayer networks are the key to incorporation of the immiscible components and form a broad damping functional region. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 545–551, 2002     

Morphology development in polychloroprene–polystyrene latex interpenetrating polymer networks

Latex interpenetrating polymer networks (LIPNs) have been prepared using a crosslinked polychloroprene latex as the seed emulsion, followed by the in situ polymerization of styrene, typically with a 10% divinyl benzene crosslinker. Polychloroprene–crosslinked polystyrene (XPS) ratios ranging from 70/30 to 40/60 were used, with the second monomer being added as a single aliquot rather than by “starvation” routes. The majority of the work has been conducted using the water‐soluble persulfate initiator method, which entails lengthy (∼ 6 h) polymerizations. To follow the development of microstructure, polymerizations were also stopped at 0.5, 1, and thence hourly intervals up to 6 h, so that any effect of time on shell and domains could be seen by transmission electron microscopy (TEM). Parallel studies using azo‐bis(isobutyronitrile) (AIBN) as initiator at the same temperature were conducted. Products were also studied, after staining, by TEM. For the persulfate initiator, domain structures predominated for the 70/30 ratio, but polystyrene‐rich shells are found in all cases, with increasing thickness as the chloroprene/styrene ratio was reduced. The styrene‐rich products (i.e., 40/60 Neoprene/XPS ratio) appear to have larger unstained domains suggesting phase separation. For the AIBN‐initiated styrene polymerization, shells are less evident, and where they exist, are both thinner and less continuously developed. Domain sizes are somewhat larger. This relatively hydrophobic initiator has caused polymerization predominately in the interior of each latex particle. The particle size distribution of the seed neoprene latex is broad and bimodal. As the LIPNs form, the larger diameter component increases and little evidence for fresh nucleation, in the form of small diameter particles, is seen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 629–638, 1999     

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。     

胶乳型互穿网络聚合物的研究

综述了胶乳型互穿网络聚合物的研究,着重介绍了合成工,乳胶粒形态结构的影响因素,同时亦对胶乳型互穿网络聚合物的性能作了介绍。     

Synthesis,characterization, and properties of interpenetrating polymer networks containing functionalized latex particles

Three-component interpenetrating polymer networks (IPNs) comprising polyurethane (PUR), poly(n-butyl methacrylate) (PBMA), and polystyrene (PS) latex particles were prepared in a modified one-shot synthesis. The hydroxy-functionlized and unmodified polystyrene latex particles were synthesized via a seeded emulsion polymerization. The incorporation of hydroxyethyl methacrylate into the latex particles was confirmed via diffuse reflectance infrared analysis and modulated-temperature differential scanning calorimetry. The IPNs were characterized by dynamic mechanical thermal analysis, tensile testing, hardness measurements, and transmission electron microscopy. The three-component materials exhibited higher values for the Young's modulus and the Shore A hardness and for the dynamic storage modulus in the higher temperature range from 80 to 140°C than did the PUR/PBMA IPN alone. The latex particles with the hydroxyl functionality exhibited a better miscibility with the microheterogeneous PUR/PBMA IPN than did unfunctionalized PS latex particles, and, therefore, resulted in materials with better damping properties in the temperature range between 80 and 140°C. Transmission electron micrographs confirmed the imporved miscibility of the functionalized latex particles. The latex particles were not, however, dispersed on an individual level but formed agglomerates of between 2 and 20 μm. © 1996 John Wiley & Sons, Inc.     

Synthesis and behavior of poly(vinyl chloride)-based latex interpenetrating polymer networks

Poly(vinyl chloride)/poly(butadiene–co–acrylonitrile) interpenetrating polymer networks (IPN's) were synthesized in latex form. Dynamic mechanical spectroscopy as a function of temperature revealed that the glass transitions of the individual networks were broadened and in some cases spanned the entire temperature range between the two individual polymer transitions. This was interpreted to indicate extensive but incomplete mixing between the two networks. Depending on overall composition, the cast or molded films were either plastic or tough elastomers at room temperature. Some aspects of phase continuity and structure, including a graded core-shell model, are discussed.     

Acronal-polymethyl acrylate interpenetrating polymer networks

Four interpenetrating polymer networks were prepared by swelling crosslinked Acronal (a copolymer of styrene and butyl acrylate) with methyl acrylate plus crosslinking agent and then polymerizing the methyl acrylate in situ. Certain properties of the constituent network materials, plus the interpenetrating polymer networks which contained 70, 50, 35 and 25% by weight of polymethyl acrylate, were investigated. Electron microscopy showed the interpenetrating polymer networks to be two-phase materials with the polymethyl acrylate domain size increasing with increasing polymethyl acrylate content. Longitudinal sonic velocity measurements indicate that at around 50% by weight of polymethyl acrylate both phases become continuous while dynamic mechanical spectroscopy leads to the view that the constituent networks were not extensively mixed.     

Elastomeric domain-type interpenetrating polymer networks

Elastomeric latex interpenetrating polymer networks (IPNs) can result from a two-stage emulsion polymerization procedure in which styrene is polymerized and cross-linked on a lightly cross-linked polyacrylate (PA) seed latex in a ratio of 75 : 25 PA-PS. The multiphase nature of these IPNs is indicated by two distinct T_gs and is confirmed by cold-stage transmission electron microscopy and by the unique mechanical and rheological properties that are intimately related to the material's structure. PS microdomains reinforce the elastomeric PA, yielding a significant modulus, and interparticle PS physical ties yield a significant ultimate tensile strength. The elastomeric latex IPN's dual thermoset-thermoplastic nature is revealed in a stick, slip, roll flow mechanism of the cross-linked submicrometer particles, which can be injection molded as a thermoplastic. The relationships among the polymerization procedure, the structure, and the physical properties are characterized by the examination of several different materials using a variety of analytic techniques.     

聚丙烯酸乙酯/聚异冰片酯镶嵌型乳液互穿聚合物网络

用多步种子乳液聚合法合成了微交联结构的复合乳液聚丙烯酸乙酯(xPEA)／聚异冰片酯(xPIBA)。利用异冰片酯超大的侧基得到具有很高Tg的聚合物的复合物。TEM照片显示，这种乳液具有镶嵌式的结构，DSC分析表明，2种聚合物之间是互穿聚合物网络的关系。当xPEA／xPIBA的质量比为75／25，其中二者TEGDA质量分数分别为0．5％和0．15％时，塑性加工后，试样拉伸强度可达6．8MPa，扯断伸长率为412％，永久变形小于50％。试样在120℃仍然保持3.5MPa的拉伸强度。     

Glass transition behavior of latex interpenetrating polymer networks based on methacrylic/acrylic pairs

Interpenetrating polymer networks (IPN's) of poly(alkyl methacrylates) and poly(alkyl acrylates) have been synthesized in latex form. Dynamic mechanical spectroscopy studies on these materials revealed extraordinarily broad glass transition regions, illustrating the semicompatible nature of these materials. In a true synergistic effect, the value of tan δ remains high and nearly constant over a broad temperature range for select compositions, emphasizing their potential value in noise and vibration damping applications. Compositionally identical latex IPN pairs were prepared by slow and rapid addition of monomer. The mechanical behavior of the resulting materials was similar and can be explained in terms of the core-shell model. A 50/50 isomeric homologous series of compositions was examined. After taking into account the relative difference between the glass transition temperatures of the methacrylic/acrylic pair, no substantial change in compatibility was noted throughout the series. Because the acrylic monomer II is roughly equally solvated by both the previously formed methacrylic polymer I and the nascent acrylic polymer II, extensive polymer I/polymer II mixing is encouraged, and sharp phase separation discouraged in these materials.     

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。     

Phase distribution and separation in poly(2-acetoxyethyl methacrylate)/polystyrene latex interpenetrating polymer networks

A series of latex interpenetrating polymer networks (LIPNs) were prepared via two-stage soap-free emulsion polymerization of styrene on cross-linked poly(2-acetoxyethyl methacrylate) (PAEMA) seed latexes, using potassium persulfate as initiator. It was found that a compositional gradient was present when PAEMA seeds cross-linked either lightly or highly were used. The polystyrene (PS) phase is localized near the particle center in the former case, while it is segregated near the surface in the latter case. A uniform distribution of PS phase in LIPN was formed, if moderately cross-linked PAEMA seed was used. All the LIPNs appeared to be microphase-separated, and increase of cross-linking degree in seed latexes decreased the PS-rich domain size. The results were explained by the particle growth mechanism that involved the formation of surface-active oligomeric radicals in water phase, adsorption of the radicals onto monomer-swollen particle/water interface, and chain propagation in the interface with subsequent phase migration dominated by the competitive effects of thermodynamics and kinetics.     

Study of the synthesis and properties of PBA/PS/PMMA latex interpenetrating polymer networks

In this article, we use the technique of multistage emulsion polymerization to synthesize the LIPN PBA/PS/PMMA and use the gravimetric analysis method to study the apparent kinetics of the reaction process and to investigate the influence of the concentration of the initially emulsifying agent, the initiator, and the extent of the crosslinking on the distribution of the particle diameter and the dynamic mechanical properties of the products.     

Recent advances in interpenetrating polymer networks

Interpenetrating polymer networks (IPN's) can be defined as a combination of two polymers in network form, at least one of which was synthesized and/or crosslinked in the immediate presence of the other. Historically, the science of IPN's began with the papers of J. R. Millar in 1960 on homo-IPN's made from polystyrene, but the first recorded publication is a patent by J. W. Aylsworth in 1914. This latter system was based on phenol-formaldehyde for one network, and sulfur cured natural rubber for the other network. Early academic laboratories interested in IPN's include the Frisch team at Detroit and SUNY, who soon added their former student, Danny Klempner, and Yuri Lipatov's team at the Ukranian SSR Academy of Sciences in the USSR, as well as the author's laboratory. More recent academic teams interested in IPN's include Douglas Hourston at the University of Lancaster, England; Robert Cohen at MIT; S. C. Kim at the Korea Advanced Institute of Science and Technology, Seoul, Korea; G. Meyer and J. M. Widmaier in Strasbourg, France; and many others. Numerous industrial laboratories are interested, noting that about 90 U.S. patients have been granted, most of them in the past ten years. Systems of special interest include the new thermoplastic IPN's, which are really hybrid materials between polymer blends and IPN's, and the IPN-based RIM (reaction injection molding) materials. Other materials include the sequential IPN's and the SIN's, which have both polymers simultaneously polymerized, and the latex IPN's, which often exhibit core-shell characteristics.     

Thermodynamic characterization of interpenetrating polymer networks

Crosslinked poly(methyl methacrylate) (PMMA-c), poly(carbonate-urethane) (PCU-c), poly(vinyl pyridine) (PVP-c), and full, simultaneous interpenetrating polymer networks (IPNs) based on the above polymers were characterized by precise heat capacity (C_p) measurements in the temperature interval 4.2–450 K. The raw values of C_p scaled with temperature (T) as C_p ∼ T^d with d = 2 and 5/3, as expected for a fracton-like vibration regime, in the temperature intervals 8–10 and 10–30 K, respectively. A single glass transition temperature (T_g) and two T_g's were observed for apparently homogeneous and microphase-separated IPNs, respectively. Judged by the positive sign of the excess Gibbs free energy, the apparently single-phase state of homogeneous IPNs is thermodynamically unstable; however, its kinetic stability is ensured by permanent topological constraints (network junctions) prohibiting the incipient phase separation.