Sequential interpenetrating polymer network based on nitrile–phenolic blend and poly(alkyl methacrylate)

Interpenetrating polymer networks (IPNs) based on a nitrile rubber (NBR)–phenolic resin (PH) blend and poly(alkyl methacrylates) were synthesized by a sequential method. The cured blends were swollen in a methacrylate monomer containing a crosslinker and initiator. The swollen rubber sheets were cured at 60°C. From the swelling study of the monomer, it was found that IPN formation in the blend is in between the rubber and poly(alkyl methacrylate) phases only. The IPNs thus formed were characterized for their tensile, dynamic mechanical, and solvent-resistance characteristics. The tensile strength of the IPNs are dependent on the PH content; at a lower content of PH (up to 20 parts), IPNs have a higher strength compared to their corresponding blends, whereas at a higher content of PH (beyond 30 parts), the strength decreases. But for every NBR/PH-fixed composition, the strength of IPNs was found to be increasing in the order of PBuMA < PEMA < PMMA. The dynamic property results showed that NBR/PH blends are incompatible. The storage modulus of IPNs are always higher than their corresponding blends at all temperatures. The tan δ peaks of IPNs are broad, indicating the presence of microphase-separated domains. The IPNs show superior solvent-resistance characteristics compared to the blends. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68:255–262, 1998     

Interpenetrating polymer networks based on nitrile rubber and metal methacrylates

Interpenetrating polymer networks (IPNs) based on nitrile rubber (NBR) as first component and zinc dimethacrylate (ZnDMA), aluminum trimethacrylate (AlTMA), or zirconium tetramethacrylates (ZrTeMA) as second component were synthesized. Sequential IPNs (SeqIPN) were formed by two routes such as compression molding (CM) and swelling/curing (SC). The IPNs were found to have superior properties compared to metal oxide/hydroxide‐filled NBR. Tensile strength has increased to a large extent while maintaining appreciable elongation. Total crosslink density (covalent and ionic) was found to increase in the order NBR/metal oxide or hydroxide < SeqIPN(CM route) < SeqIPN (SC route). IPNs are found to retain high storage modulus even in the rubbery region. It is observed that change of technique for IPN formation has drastically changed the modulus of the present system. Decrease in tan δ value and inward shifting of peaks were observed because of IPN formation. Morphology of SeqIPN by SC process was found to be more uniform compared to others. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2542–2548, 2006     

Sequential interpenetrating polymer network based on styrene butadiene rubber and polyalkyl methacrylates

A series of sequential interpenetrating polymer network (IPNs) based on styrene butadiene rubber (SBR) and polyalkyl (methyl, ethyl, and butyl) methacrylates have been prepared by using tetraethylene glycol dimethacrylate as crosslinker. The IPNs were characterized by infrared spectrophotometer, dynamic mechanical analyzer, thermogravimetric analyzer, and swelling study. IPNs have exhibited higher tensile properties compared with pure SBR. IPNs based on PMMA have shown higher tensile strength compared with others. Dynamic mechanical analysis has shown that the IPNs have superior dynamic properties than SBR. Because of IPN formation, tan δ peak shifted inward between SBR and acrylates. Although the magnitude of tan δ decreased, the peaks were broadened because of micro heterogeneous phase separation. At higher concentration of methacrylate, splitting in tan δ peak was noticed because of phase separation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1120–1126, 2007     

Interpenetrating polymer networks based on carboxylated nitrile rubber and poly(alkyl methacrylate)s

A series of interpenetrating polymer networks (IPNs) based on carboxylated nitrile rubber (XNBR) and poly(alkyl methacrylate)s such as poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA) and poly(butyl methacrylate) (PBuMA) were synthesized. The compositions of the IPNs were also varied by changing the swelling time of the rubber in the methacrylate monomer. The tensile and dynamic mechanical properties of the IPNs were studied. The dynamic mechanical properties in the range of 1–10⁵ Hz were obtained by the time‐temperature superposition of the data under multifrequency mode, which indicated high tanδ with good storage modulus in the entire frequency range. This indicates the suitability of these IPNs as vibration and acoustic dampers.     

Studies on IPNS based on nitrile rubber and polyalkyl methacrylates

Sequential interpenetrating polymer networks (IPNs) based on nitrile rubber and various types of polyalkyl methacrylates such as poly(n-butyl methacrylate), poly(ethyl methacrylate), and poly(methyl methacrylate) were synthesized. The compositions of the IPNs could be varied by varying the reaction parameters such as swelling time and concentration of crosslinker. The tensile properties of the IPNs show that with increase in bulkiness of the ester group of the acrylates the tensile strength decreases, whereas elongation at break increases because of decreased stiffness of the acrylate phase. The dynamic modulus and loss tangent of the IPNs also show similar trend because of the above reason. All the IPNs were also tested for dynamic properties under multifrequency mode, and with the help of the WLF equation, the behavior of these IPNs in the frequency range of 1–10⁵ Hz were evaluated. The results showed reasonably high tan δ with good storage modulus in the entire frequency range for all the IPNs. © 1997 John Wiley & Sons, Inc. J Appl Polm Sci 65:549–554, 1997     

Dynamic mechanical properties of semi‐interpenetrating polymer network‐based on nitrile rubber and poly(methyl methacrylate‐co‐butyl acrylate)

In this article, semi‐interpenetrating polymer network (Semi‐IPNs) based on nitrile rubber (NBR) and poly(methyl methacrylate‐co‐butyl acrylate) (P(MMA‐BA)) were synthesized. The structure and damping properties of the prepared Semi‐IPNs blends were characterized and by fourier transform infrared spectrum (FTIR), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), thermogravimetric analysis (TGA/DTG), and tensile mechanical properties. The results showed that interpenetrating network based on P(MMA‐BA) and NBR was successfully obtained, which showed the improved thermal stability compared to NBR/P(MMA‐BA)‐based two‐roll mill blends. Furthermore, Semi‐IPNs showed significantly better the dynamic mechanical properties than that of the two‐roll mill system. With the increasing feed ratio of BA and MMA during the preparation of Semi‐IPNs, the loss peak position for P(MMA‐BA) in NBR/PMMA IPNs shifted to a lower temperature from 20°C to ?17°C, and when NBR in Semi‐IPNs was accounted for 40 wt %, the dynamic mechanical thermal analysis showed that much more advanced damping material with wider temperature range (?30°C < T < 80°C) as tan δ > 0.45 can be achieved. Therefore, it was expected as a promising way to obtain the excellent damping materials with good oil‐resisted properties according the Semi‐IPNs system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40217.     

Miscibility and thermal and dynamic mechanical behaviour of semi‐interpenetrating polymer networks based on polyurethane and poly(hydroxyethyl methacrylate)

The thermodynamic miscibility and thermal and dynamic mechanical behaviour of semi‐interpenetrating polymer networks (semi‐IPNs) of crosslinked polyurethane (PU) and linear poly(hydroxyethyl methacrylate) (PHEMA) have been investigated. The free energies of mixing of the semi‐IPN components have been determined by the vapour sorption method and it was established that the parameters are positive and depend on the amount of PHEMA in the semi‐IPN samples. Thermal analyses glass transition temperatures evidenced two in the semi‐IPNs in accordance with the investigation of the thermodynamic miscibility of these systems. Dynamic mechanical analysis revealed a pronounced change in the viscoelastic properties of the PU‐based semi‐IPNs with different amounts of PHEMA in the samples. The semi‐IPNs have two distinct tan δ maxima related to the relaxations of the two polymers in their glass temperature domains. The temperature position of PU relaxation maximum tan δ is invariable but its amplitude decreases in the semi‐IPNs with increasing amount of PHEMA in the systems. The tan δ maximum of PHEMA is shifted to a lower temperature and its amplitude decreases with increasing amount of PU in the semi‐IPNs. The segregation degree of components α was calculated using the viscoelastic properties of semi‐IPNs. It was concluded that the studied semi‐IPNs are two‐phase systems with incomplete phase separation. The different levels of immiscibility lead to the different degree of phase separation in the semi‐IPNs with compositions. Copyright © 2004 Society of Chemical Industry     

Damping analysis of polyurethane/polyacrylate interpenetrating polymer network composites filled with graphite particles

The graphite‐filled polyurethane/poly(methyl methacrylate‐butyl methacrylate) (PU/P(MMA‐BMA)) semi‐interpenetrating polymer networks (IPNs) were synthesized by sequential method. The influences of graphite particle content and size on the 60/40 PU/P(MMA‐BMA) IPNs were studied. The damping properties of IPN composites were evaluated by dynamic mechanical thermal analysis (DMA) and cantilever beam resonance methods. The mechanical performances were investigated using tensile and hardness devices. DMA results revealed that the incorporation of graphite particles improved damping properties of IPNs significantly. The 5% graphite‐filled IPN composite exhibited the widest temperature range and the highest loss factor (tan δ) when the test frequency was 1 Hz. As to the damping properties covering a wide frequency range from 1 to 3,000 Hz, the addition of graphite particles broadened the damping frequency range (Δf, where tan δ is above 0.3) and increased the tan δ value of IPNs. Among them, the composite with 7.5% graphite showed the best damping capacity. And the hardness and the tensile strength of IPN composites were also improved significantly. POLYM. COMPOS., 2013 © 2013 Society of Plastics Engineers     

DMA analysis of the damping of ethylene–vinyl acetate/acrylonitrile butadiene rubber blends

The mechanical and damping properties of blends of ethylene–vinyl acetate rubber (VA content > 40% wt) (EVM)/acrylonitrile butadiene rubber (NBR), with 1.4 phr BIPB [bis (tert‐butyl peroxy isopropyl) benzene] as curing agent, were investigated by DMA and DSC. The effect of chlorinated polyvinyl chloride (CPVC), silica, carbon black, and phenolic resin (PF) as a substitute curing agent, on the damping and mechanical properties of EVM/NBR blends were studied. The results showed that 10 phr CPVC did not contribute to the damping of EVM700/NBR blends; Silica could dramatically improve the damping of EVM700/NBR blends because of the formation of bound rubber between EVM700/NBR and silica, which appeared as a shoulder tan δ peak between 20 and 70°C proved by DMA and DSC. This shoulder tan δ peak increased as the increase of the content of EVM in EVM/NBR blends. The tensile strength, modulus at 100% and tear strength of the blend with SiO₂ increased while the elongation at break and hardness decreased comparing with the blend with CB. PF, partly replacing BIPB as the curing agent, could significantly improve the damping of EVM700/NBR to have an effective damping temperature range of over 100°C and reasonable mechanical properties. Among EVM600, EVM700, and EVM800/NBR/silica blend system, EVM800/NBR/silica blend had the best damping properties. The EVM700/NBR = 80/10 blend had a better damping property than EVM700/NBR = 70/20. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

丁腈橡胶/聚氯乙烯共混物的阻尼性能

考察了丁腈橡胶/聚氯乙烯共混物中硫化体系、炭黑种类、增塑剂用量及组分比对材料阻尼性能的影响.结果表明,丁腈橡胶/聚氯乙烯共混物的交联密度增大,其损耗因子峰向高温方向移动,峰值升高,损耗因子不小于0.5的温度区域变窄;相比高耐磨炭黑而言,用半增强炭黑作填料可使丁腈橡胶/聚氯乙烯共混物呈现更好的阻尼性能;随着增塑剂邻苯二甲酸二辛酯用量的增加,共混物的损耗因子峰值升高,但该峰向低温方向移动;丁腈橡胶/聚氯乙烯共混物(质量比为70/30)的损耗因子不小于0.5的阻尼温域相对较宽,适用于常温,且力学性能较好.     

Electron beam effects on polymers: V. Symmetric and asymmetric materials based on the controlled distribution of bis-GMA into crosslinked nitrile rubber films prior to curing by electron beam radiation

Two systems based on the controlled distribution of the methacrylic acid derivative of the diglycidyl ether of bisphenol-A (bis-GMA) into crosslinked acrylonitrile–butadiene co-polymers, commonly called nitrile rubber (NBR), were prepared utilizing electron beam (EB) radiation. In the system called “symmetric,” the EB crosslinked NBR was swollen to equilibrium in solutions containing different concentrations of bis-GMA. The swollen NBR film was then EB irradiated to different dosage levels. The other system, called “asymmetric” or “gradient,” was prepared by applying the solutions containing bis-GMA to one surface of the EB crosslinked NBR film in a controlled time that was less than the time to achieve an equilibrium concentration across the thickness or “swelling” dimension. This asymmetrically swollen NBR film was then immediately EB irradiated using different dose levels. The prepared symmetric and asymmetric NBR systems were investigated by thermal and mechanical, as well as microscopic, analyses. The mechanical responses were shown to be strongly dependent on the bis-GMA content in the NBR film and the type of preparation history. The dynamic mechanical spectra showed the presence of two transitions, indicating some level of phase separation that was supported by scanning electron microscopy of fracture surfaces for symmetric and asymmetric systems. The asymmetric distribution of the imbided (cured) monomer in the asymmetric system was confirmed by both FT-IR and optical microscopy analyses.     

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.     

Studies on castor oil–based polyurethane/polyacrylonitrile interpenetrating polymer network for toughening of unsaturated polyester resin

Tricomponent interpenetrating polymer network (IPN) systems involving castor oil, toluenediisocyanate (TDI), acrylonitrile (AN), ethylene glycol diacrylate (EGDA), and general‐purpose unsaturated polyester resin (GPR) were prepared with various compositions. The structures of the IPNs at various stages were confirmed using FTIR. The thermal stability of the IPNs was studied using TGA, which indicated that the polyurethane/polyacrylonitrile/GPR (PU/PAN/GPR) IPN underwent single‐stage decomposition, showing perfect compatibility at the IPN composition of 10 : 90 (PU/PAN : GPR). The mechanical properties such as tensile, flexural, impact, and hardness for the IPNs with various compositions were determined. It was found that the tensile strength of the GPR matrix was decreased and flexural and impact strengths were increased upon incorporating PU/PAN networks. The swelling properties in water and toluene were also studied. The morphology of the IPNs was studied using SEM. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 817–829, 2004     

撕裂模式下乙烯-丙烯酸共聚物/丁腈橡胶热塑性硫化胶的Mullins效应及其可逆回复

采用动态硫化法制备了乙烯-丙烯酸共聚物(EAA)/丁腈橡胶(NBR)热塑性硫化胶(TPV),对其撕裂强度、微观相结构、撕裂模式下的Mullins效应及热处理条件下的Mullins效应可逆回复行为进行了研究.结果表明,EAA/NBR TPV在EAA与NBR的质量比为40/60时的撕裂强度和应变较高.微观形貌观察可见,EA...     

Study on the damping of EVM based blends

The mechanical and damping properties of blends of ethylene‐vinyl acetate rubber(VA content >40 wt %) (EVM)/nitrile butadiene rubber (NBR) and EVM/ethylene‐propylene‐diene copolymer (EPDM), both with 1.4 phr BIPB (bis (tert‐butyl peroxy isopropyl) benzene) as curing agent, were investigated by DMA. The effect of polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), and dicumyl peroxide (DCP) on the damping and mechanical properties of both rubber blends were studied. The results showed that in EVM/EPDM/PVC blends, EPDM was immiscible with EVM and could not expand the damping range of EVM at low temperature. PVC was miscible with EVM and dramatically improved the damping property of EVM at high temperature while keeping good mechanical performance. In EVM/NBR/PVC blends, PVC was partially miscible with EVM/NBR blends and remarkably widened the effective damping temperature range from 41.1°C for EVM/NBR to 62.4°C, while CPVC mixed EVM/NBR blends had an expanded effective damping temperature range of 63.5°C with only one damping peak. Curing agents BIPB and DCP had a similar influence on EVM/EPDM blends. DCP, however, dramatically raised the height of tan δ peak of EVM/NBR = 80/20 and expanded its effective damping temperature range to 64.9°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

NBR对白炭黑-炭黑填充补强SSBR性能的影响

研究了不同用量的丁腈橡胶(NBR)对白炭黑-炭黑填充溶聚丁苯橡胶(SSBR)性能的影响。研究证明：随着NBR用量的增加,混炼胶硫化速度加快,正硫化时间呈减小趋势,压缩生热和永久变形率缓慢增大,拉伸强度略有下降,但是可以提高耐磨耗性能;当加入NBR的量为4份时可以同时优化胶料湿滑性能和滚动阻力。     

Aluminum powder filled nitrile rubber composites

Effect of aluminum powder on the properties of nitrile rubber (NBR) composites and the role of bonding agent viz. hexamethylene tetramine‐resorcinol has been investigated. Shore A hardness of the aluminum powder filled composites is lower than that of high abrasion furnace (HAF) and acetylene black (ACB) filled nitrile rubber composites and can be increased by the addition of bonding agent. Equilibrium swelling decreased considerably by the use of hexamethylene tetramine‐resorcinol, suggesting an improved nitrile rubber–aluminum powder adhesion. A marked increase in thermal conductivity is obtained with the incorporation of aluminum powder. Increased thermal conductivity reduced the additional time needed for the vulcanization of thick rubber articles and imparted uniform curing throughout the material. In nitrile rubber, the modulus and tensile strength followed the order HAF > ACB > aluminum powder. Combination of HAF and aluminum powder in NBR gave composites with good thermal conductivity and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3156–3161, 2004     

Mechanical and viscoelastic properties of semi‐interpenetrating polymer networks of poly(vinyl chloride)/thermosetting resin blends

Semi‐interpenetrating polymer networks (SIPNs) of PVC/thermoset were prepared by premixing porous, 150 μm diameter particles of PVC and a small quantity (from 5 to 15% by weight) of a single thermosetting liquid preresin from one of five types (e.g. methylene bis‐phenyl diisocyanate (MDI), oligomeric MDI isocyanates (PAPI), toluene diisocyanate (TDI) prepolymer, epoxy, and vinyl ester resins, respectively). Two roll milling of these mixtures was followed by hot‐press curing. Mechanical testing indicated that most of these blends exhibited increased tensile, impact, and flexural strengths. The strength increments were greater when going from 0 to 5% thermoset content than when going from 5 to 10% or 10 to 15% thermoset. In many cases, increasing thermoset content from 10 to 15% gave slightly decreased or unchanged tensile, impact, and flexural strengths. This behavior is in accord with a “thermoset dilution effect” in PVC. Most of these SIPN blends exhibited a tan δ peak temperature lower than that for pure PVC in the glass transition region. The tan δ peak temperatures were progressively lowered as the amounts of thermoset increased. Also, a single distinct peak existed in the E″ curves for most of the blends. Only the PVC/epoxy (90/10) blend showed two peak maxima in E″ vs. temperature curves. All blends exhibited peak E″ values at a lower temperature than those of PVC which had been exposed to the same processing temperatures. These observations seem to rule out the presence of large domains of PVC, which are phase‐separated from PVC/thermoset SIPN, and pure thermoset domains. A substantial amount of the added thermoset appears to exist in SIPN type phases in these five blend types.     

Morphology,mechanical properties,and failure topography of semi‐interpenetrating polymer networks based on natural rubber and polystyrene

Semi‐interpenetrating networks (semi‐IPNs) were prepared from natural rubber (NR) and polystyrene (PS) by the sequential method. In these semi‐IPNs the NR phase was crosslinked while the PS phase was uncrosslinked. Different initiating systems such as dicumyl peroxide (DCP), benzoyl peroxide (BPO), and the azobisisobutyronitrile (AIBN) system were used for polymerizing the PS phase. The blend ratio was varied by controlling the swelling of NR in the styrene monomer. The mechanical properties of the semi‐IPNs, namely, density, tensile strength, tear strength, elongation at break, tension set, tensile set, impact strength, and hardness, were determined. The morphology of different IPNs was studied using scanning electron microscopy. A compact morphology with a homogeneous phase distribution was observed in the semi‐IPNs. The properties of the semi‐IPN do not change much with the initiating system. However, in most cases, the DCP initiating system showed slightly superior performance. The tensile and tear‐strength values of the IPNs were found to increase with increasing plastomer content. The crosslink density of the semi‐IPNs also increased with increase in the polystyrene content. The experimental values were compared with theoretical models such as series, parallel, Halpin Tsai, Coran, Takayanaki, Kerner, and Kunori. The tensile and tear‐fracture surfaces were examined using a scanning electron microscope. The fracture patterns were correlated with the strength and nature of the failure. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2327–2344, 2000     

Solvent resistance and mechanical properties in thermoplastic elastomer blends prepared by dynamic vulcanization

Dynamic vulcanization was used to prepare thermoplastic elastomer blends of nylon (polyamide), polypropylene (PP) and polybutylene terephthalate thermoplastics with chlorobutyl (CIIR) and nitrile (NBR) rubbers. Mechanical properties of the blends were correlated against composition. Although hardness and tensile strength increase with increasing thermoplastic content for all blends, elongation at break values initially decrease and then increase in the range of 20–40% thermoplastic. For various blend compositions, the swelling behavior was evaluated with solvents that are able to dissolve the uncured rubber portion but not the thermoplastic component of the mixtures. All five systems showed swelling index values that were substantially less than the calculated “theoretical” values of swelling index. This was attributed to a caging effect of the thermoplastic component on the rubber phase, which restricts access of solvent and swelling of the rubber phase. In turn, this affects the solvent resistance of the blend. Some of the blends were evaluated by differential scanning calorimetry to assess the compatibility of the components in the blend. scanning electron microscopy was also used to determine the degree of compatibility of the two phases generated in the mixing process. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008