Epoxy resin–poly(ethyl methacrylate) interpenetrating polymer networks: Morphology,mechanical, and thermal properties

Full (interpenetrating networks (IPNs)) and semi-IPNs of the epoxy resin and poly(ethyl methacrylate) (PEMA) were prepared by the sequential mode of synthesis. These were characterized with respect to their mechanical properties, namely, tensile strength, elongation at break, modulus, and toughness. Thermal properties were studied by differential scanning calorimetry and thermogravimetry. The morphological features were studied through scanning electron microscopy (SEM) and polarized light microscopy. The effects of variation of the blend ratios on the above-mentioned properties were examined. There was a gradual decrease of modulus and tensile strength with consequent increases in elongation at break and toughness for both types of IPNs with increases in PEMA content. The weight retentions in the thermal decomposition of both the semi-IPNs and full IPNs were higher than the epoxy homopolymer. This enhancement was presumably related to the presence of the unzipped ethyl methacrylate monomer, which acted as radical scavengers in the epoxy degradation. An inward shift and lowering (with respect to pure epoxy) of the T_g of the IPNs was observed. The polarized light microscopy exhibits bimodal distribution of particle sizes. The fractography as studied by SEM shows change in fracture mechanics from shear yielding to crazing with increasing PEMA content. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1051–1059, 1998     

Interpenetrating polymer networks based on uralkyd–butylmethacrylate

Two-component semi- and full-interpenetrating polymer networks (IPNs) of hydrogenated castor oil based uralkyd resin (UA) and poly(butylmethacrylate) (PBMA) were synthesized by the sequential technique. The elastomers obtained were characterized with respect to their mechanical properties such as tensile strength, elongation at break and hardness (Shore A). The apparent densities of these samples were determined and compared. Glass transition studies were carried out using differential scanning calorimetry. The thermal characterization of the elastomers was undertaken with the aid of thermogravimetric analysis. Phase morphology was studied by scanning electron microscopy. The effect of the variations of UA–PBMA on the above-mentioned properties was examined. The elongation percentage at break showed higher values in the case of all the semi-IPNs as compared to the full-IPNs.     

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     

New interpenetrating polymer networks based on uralkyd–poly(butyl methacrylate)

A study on two‐component semi‐ and full‐interpenetrating polymer networks (IPNs) of soyabean‐oil based uralkyd resin (UA) and poly(butyl methacrylate) (PBMA) synthesized by a sequential technique, has been conducted. The IPNs obtained are characterized with respect to their mechanical properties, such as tensile strength, percentage elongation and hardness (Shore A). Phase morphology has been studied by scanning electron microscopy. Glass transition studies have been carried out using differential scanning calorimetry. The thermal characterization of the IPNs was undertaken with the aid of thermogravimetric analysis. The apparent densities of these samples have been determined and are compared. The effect of the compositional variation on the above‐mentioned properties was examined. The tensile strength exhibits a sudden rise (approximately three‐fold) for the semi‐ and full‐IPNs with composition UA: PBMA 40% : 60% compared with the UA:PBMA composition of 20% : 40%. © 2001 Society of Chemical Industry     

Novolac resin–poly(ethyl methacrylate) interpenetrating polymer networks: Morphology and mechanical and thermal properties

Full interpenetrating networks (IPNs) and semi‐IPNs of Novolac (phenolic) resin and poly(ethyl methacrylate) (PEMA) were prepared by the sequential mode of synthesis. These were characterized with respect to their mechanical properties, that is, ultimate tensile strength (UTS), percentage elongation at break, modulus, and toughness. Thermal properties were studied by DSC and thermogravimetric analysis (TGA). The morphological features were studied through polarizing light microscopy (PLM). The effects of variation of the blend ratios on the above‐mentioned properties were examined. There was a gradual decrease of modulus and UTS with consequent increases in elongation at break and toughness for both types of IPNs with increasing proportions of PEMA. An inward shift and lowering (with respect to pure phenolic resin) of the glass‐transition temperatures of the IPNs with increasing proportions of PEMA were observed, thus indicating a plasticizing influence of PEMA on the rigid and brittle matrix of crosslinked phenolic resin. The TGA thermograms exhibit two‐step degradation patterns. Although there was an apparent increase in thermal stability at the initial stages, particularly at lower temperatures, a substantial decrease in thermal stability was observed in the regions of higher temperatures. The surface morphology as revealed by PLM clearly indicates two‐phase structures in all the full and semi‐IPNs, irrespective of PEMA content. The matrix–PEMA domain interfaces are quite sharp at higher concentrations of PEMA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 412–420, 2003     

Epoxy/poly(methyl methacrylate) interpenetrating polymer networks—morphology,mechanical and thermal properties

Full and semi-IPNs were prepared from epoxy and poly methyl methacrylate (PMMA), by the sequential mode of synthesis and were characterized by measurements of ultimate tensile strength (UTS), elongation at break, modulus, and toughness. Aromatic polyamine adducts and ethylene glycol dimethacrylate were used as the crosslinkers for epoxy and comonomer/crosslinker for methyl methacrylate monomer, respectively. Higher UTS and modulus of the semi-IPNs over full IPNs were attributed to the higher probability of interpenetration. The weight retention in the thermal decomposition of the IPNs and semi-IPNs were higher than the epoxy homopolymer. This enhancement was presumably related to the presence of the unzipped methyl methacrylate monomer which acted as radical scavangers in the epoxy degradation. © 1994 John Wiley & Sons, Inc.     

Engineering properties of Novolac resin‐PMMA{poly(methyl methacrylate)} IPN system

Full and semi interpenetrating polymer networks (IPNs) based on phenol‐formaldehyde resin (Novolac) and poly(methyl methacrylate) have been made by in situ sequential technique of IPN formation. These systems of different compositions were characterized with respect to their mechanical properties, such as, ultimate tensile strength (UTS), percentage elongation at break, modulus, and toughness. Thermal properties were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Extent of phase mixing of the two polymers was envisaged from the micrographs obtained by polarizing light microscopy (PLM). The effects of variation of the blend ratios on the above‐mentioned properties were examined. There was a decreasing trend of modulus and UTS with consequent increases in elongation at break and toughness for both types of IPNs with increase in proportions of PMMA. Lowering of glass transition temperatures (with respect to pure crosslinked Novolac resin) of the IPNs with increasing proportions of PMMA was observed, indicating a plasticizing influence of PMMA on the rigid and brittle matrix of phenolic resin. The TGA thermograms exhibit lowering in thermal stability of the IPNs with respect to pure phenolic resin in the regions of higher temperatures. With increase in proportion of PMMA the onset of degradation of the IPNs is shifted towards lower temperature zone. The surface morphology as revealed by PLM indicates distribution of discrete domains of PMMA in the phenolic resin matrix. The two phase interfaces are quite sharp at higher concentrations of PMMA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2764–2774, 2004     

Modification of novolac resin by interpenetrating network formation with poly(butyl acrylate)

Interpenetrating networks (IPNs) of novolac (phenol formaldehyde) resin and poly(butyl acrylate) (PBA) were prepared by a sequential mode of polymerization. Both full IPNs and semi‐IPNs of different compositions were synthesized and characterized with respect to their mechanical properties, that is, their modulus, ultimate tensile strength (UTS), elongation‐at‐break percentage, and toughness. Their thermal properties were examined with differential scanning calorimetry and thermogravimetric analysis (TGA). A morphological study was performed with an optical microscope. The effects of the variation of the blend ratios on the aforementioned properties were studied. There was a gradual decrease in the modulus and UTS with a simultaneous increase in the elongation‐at‐break percentage and toughness for both types of IPNs as the proportions of PBA were increased. With increasing proportions of PBA, the glass‐transition temperatures of the different IPNs underwent shifts toward a lower temperature region. This showed a plasticizing influence of PBA on the rigid and brittle phenolic matrix. TGA thermograms depicted the classical two‐step degradation for the phenolic resin. Although there was an apparent increase in the thermal stability at the initial stage (up to 350°C), particularly at lower temperatures, a substantial decrease in the thermal stability was observed at higher temperatures under study. In all the micrographs of full IPNs and semi‐IPNs, two‐phase structures were observed, regardless of the PBA content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2407–2417, 2005     

环氧树脂对过氧化物硫化丁腈橡胶性能的影响

研究了环氧树脂用量对过氧化物硫化丁腈橡胶的硫化特性及其物理机械性能的影响。结果表明,环氧树脂对正硫化时间及其拉伸性能影响较大,随着环氧树脂用量增加,正硫化时间明显缩短,拉伸强度与拉断伸长率逐渐下降,而100%定伸强度逐渐提高。差示扫描量热仪(DSC)分析发现,环氧树脂的加入能够影响硫化反应的热效应。     

Sequential interpenetrating polymer networks of novolac resin and poly(2‐ethyl hexyl acrylate)—thermal,mechanical, and morphological study

Interpenetrating polymer networks (IPN) of novolac/poly (2‐ ethyl hexyl acrylate) (PEHA) have been prepared via in situ sequential technique of IPN formation. Full and semi‐IPNs were prepared with different blend ratios (w/w) e.g., 90 : 10, 80 : 20, and 70 : 30 in which the major constituent was novolac resin. A gradual decrease in specific gravity and hardness values was observed with increase in PEHA incorporation. A steady decrease in crosslink density with increase in PEHA fraction in the IPNs was quite evident. The IPNs were characterized with respect to their mechanical properties, e.g., ultimate tensile strength, percentage elongation at break, modulus, and toughness. Thermal behavior was studied by differential scanning calorimetry and thermogravimetric analysis. A plasticizing influence of PEHA on the rigid, brittle, and hard matrix of crosslinked phenolic resin is evidenced from the mechanical and thermal properties. The two‐phase surface morphology is revealed by scanning electron microscope. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Mechanical,thermomechanical, and morphology of PVC/PBMA blends and full IPNs

Blends and full IPNs' of poly(vinyl chloride) and polybutylmethacrylate (PBMA) have been synthesized and characterized with respect to their mechanical, thermomechanical, and morphological properties. Both the systems displayed a rise in the modulus and ultimate tensile strength and a consequent decreasing tendency of elongation at break and toughness are exhibited. The influence of crosslinking of the two polymers as has been done in case of full IPNs over the ordinary blends is quite well understood from these properties. The thermomechanical analysis revealed a substantial rise in stability with increasing methacrylate concentration in the system and this is quite apparent from the softening characteristics of the different samples under study. The biphasic cocontinuous systems as explicit from the morphological studies support phase mixing at the initial stages, with subsequent phasing out tendency with increasing percentage of PBMA incorporation. The thermomechanical parameters are in conformity to their mechanicals which have been further supported by their morphological studies. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Sequential interpenetrating polymer networks of novolac resin and poly(n‐butyl methacrylate)

Novolac resin/poly(n‐butyl methacrylate), P(n‐BMA), sequential interpenetrating polymer networks (both semi and full types) were prepared and characterization of the various compositions (up to 40% by weight of PF incorporation) was performed in terms of mechanicals, namely, ultimate tensile strength (UTS), percentage elongation at break (% E.B.), modulus, and toughness. Thermal properties were studied by differential scanning calorimetry and thermogravimetric analysis (TGA). Crosslink densities of the IPNs were calculated using Flory‐Rehner equation. The morphological features were studied through scanning electron microscope. There was a gradual decrease of modulus and UTS with consequent increases in % E. B. and toughness with increasing proportions of P(n‐BMA). An inward shifting and lowering of the glass transition temperatures of the IPNs (compared with that of pure phenolic resin) with increasing proportions of P(n‐BMA) were observed. The TGA thermograms exhibit two‐step degradation patterns. A typical cocontinuous bi‐phasic morphology is evident in the micrographs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4030–4039, 2006     

Interpenetrating polymer networks based on polyol modified castor oil polyurethane and poly(2‐ethoxyethyl methacrylate): Synthesis,chemical, mechanical,thermal properties,and morphology

Interpenetrating polymer networks (IPNs) of glycerol modified castor oil polyurethane (GC‐PU) and poly(2‐ethoxyethyl methacrylate) poly(2‐EOEMA) were synthesized using benzoyl peroxide as initiator and ethylene glycol dimethacrylate (EGDM) as crosslinker. GC‐PU/poly (2‐EOEMA) interpenetrating polymer networks were obtained by transfer molding. The novel GC‐PU/poly (2‐EOEMA) IPNs are found to be tough films. These IPNs are characterized in terms of their resistance to chemical reagents thermal behavior (DSC, TGA) and mechanical behavior, including tensile strength, Young's modulus, shore A hardness, and elongation. The morphological behavior was studied by scanning electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1029–1034, 2004     

端环氧基丁腈橡胶增韧环氧树脂的结构与性能

采用端环氧基丁腈橡胶(ETBN)对环氧树脂进行增韧,研究了增韧环氧树脂浇注体的力学性能.结果表明,随着ETBN含量的增大,冲击强度、断裂伸长率明显增加,其弯曲强度、拉伸强度及拉伸模量降低,表明ETBN对环氧树脂具有明显的增韧效果.环氧树脂浇注体拉伸断面SEM照片表明,固化反应过程中ETBN均匀地分散在环氧树脂体系中.     

聚乳酸/淀粉复合材料的制备及性能研究

采用熔融共混的方法制备了聚乳酸/淀粉复合材料。通过力学测试、DSC、DMA和SEM等分析,研究了聚乳酸和淀粉在不同质量配比下,复合材料力学性能、热性能、吸水率的变化,并研究了增容剂环氧树脂对复合材料性能的影响。通过研究发现,随着淀粉含量的增加,复合材料力学性能下降,结晶度减小,储能模量降低,吸水率增大;环氧树脂的加入能提高复合材料的力学性能;SEM分析表明,聚乳酸/淀粉复合材料的断裂面呈脆性断裂特征。     

有机硅改性环氧树脂及其室温固化的性能研究

采用二苯基硅二醇(DSPD)改性双酚A型环氧树脂(E-51)制备了有机硅改性的环氧树脂,采用硫脲改性聚酰胺650制备了室温快速固化的环氧固化剂。合成产物通过红外进行表征,用盐酸-丙酮法测定改性环氧树脂的环氧值,通过指干时间确定聚酰胺650和改性聚酰胺650与E-51的较优配比。通过差示扫描量热分析法(DSC)和热重分析法(TG)表征改性环氧树脂固化物的耐热性,通过拉伸性能和扫描电镜测试(SEM)表征改性环氧树脂固化物的韧性。实验结果表明,环氧树脂经改性后,其玻璃化温度升高了27℃,与聚酰胺650固化后,固化产物的起始热分解温度明显增加,失重50%的分解温度升高了180℃,固化物的断裂伸长率增加了3.41%,断裂面呈现明显韧性断裂特征。     

Physical,mechanical, and morphological behavior of sequential polybutadiene–poly(methyl methacrylate) interpenetrating polymer networks

Both full and semi-interpenetrating polymer networks (IPNs) of polybutadiene and poly(methyl methacrylate) were synthesized by sequential polymerization. The effect of compositional variation and the cross-linking agent of both elastomer and plastomer on the physical, mechanical, and morphological properties were investigated. Full-IPNs exhibited improved tensile strength, modulus, tear strength, gel content, and density, whereas the corresponding semi-IPNs exhibited better toughness and elongation at break. Phase morphology of full-IPNs were characterized by compact, tight network structures compared to those of semi-IPNs. © 1994 John Wiley & Sons, Inc.     

Studies on the curing behavior,thermal, and mechanical properties of epoxy resin-co-amine-functionalized lead phthalocyanine

A high performance copolymer was prepared by using epoxy (EP) resin as matrix and 3,10,17,24-tetra-aminoethoxy lead phthalocyanine (APbPc) as additive with dicyandiamide as curing agent. Fourier-transform infrared spectroscopy, dynamic mechanical analysis (DMA), differential scanning calorimetric analysis (DSC), and thermogravimetric analysis (TGA) were used to study the curing behavior, curing kinetics, dynamic mechanical properties, impact and tensile strength, and thermal stability of EP/APbPc blends. The experimental results show that APbPc, as a synergistic curing agent, can effectively reduce the curing temperature of epoxy resin. The curing kinetics of the copolymer was investigated by non-isothermal DSC to determine kinetic data and measurement of the activation energy. DMA, impact, and tensile strength tests proved that phthalocyanine can significantly improve the toughness and stiffness of epoxy resin. Highest values were seen on the 20 wt% loading of APbPc in the copolymers, energy storage modulus, and impact strength increased respectively 388.46 MPa and 3.6 kJ/m², T_g decreased 19.46°C. TGA curves indicated that the cured copolymers also exhibit excellent thermal properties.     

动态固化聚丙烯／马来酸酐接枝聚丙烯／滑石粉／环氧树脂复合材料研究

将动态硫化技术应用于热塑性树脂／填料／热固性树脂复合体系，制备了动态固化聚丙烯(PP)／马来酸酐接枝PP(PP-g-MAH)/滑石粉(Talc)／环氧树脂(EP)复合材料。研究了动态固化PP／PP-g-MAH/Talc／EP复合材料的界面作用、形态结构、力学性能以及热稳定性。实验结果表明：PP／PP-g—MAH的加入，可明显增加PP/Talc复合材料的界面作用。在动态固化PP／PP-g-MAH/Talc／EP复合材料中，PP和Talc两相界面更加模糊，动态固化EP进一步增加了PP和Talc间的界面作用。当EP的用量超过5份时，部分EP呈颗粒状分布在PP基体中。与PP／PP-g-MAH/Talc／EP和PP／PP-MAH-Talc／EP复合材料相比，动态固化PP／PP-g-MAH/Talc／EP复合材料的冲击强度、拉伸强度和弯曲模量均有明显提高。当EP用量超过5份时，复合材料的冲击强度和断裂伸长率明显降低，但拉伸强度和弯曲模量继续增加。热分析表明动态固化PP／PP-g-MAH/Talc／EP复合材料具有较高的热稳定性。     

Interpenetrating polymer network from castor oil-based polyurethanes and poly(methyl acrylate). XIV

Castor oil containing hydroxyl functionality was reacted with 4,4′-diphenylmethanediisocyanate under different stoichiometric ratios of NCO/OH to obtain liquid polyurethanes. These polyurethanes were subsequently interpenetrated with methyl acrylate monomer using ethylene glycol dimethacrylate as a crosslinker by radical polymerization using benzoyl peroxide as an activator. The polyurethane/poly(methyl acrylate) interpenetrating polymer networks (PU/PMA IPNs) were obtained as tough films by transfer molding techniques. All IPNs were characterized by their resistance to chemical reagents, optical properties, thermal behavior, and mechanical properties: tensile strength, Young's modulus, elongation at break (%) and hardness Shore A. The morphology of the IPNs was studied by scanning electron microscopy and dielectric properties: electrical conductivity (σ), dielectric constant (?′), dielectric loss (?″), and loss tangent (tan δ) at different temperatures.