聚氨酯/聚甲基丙烯酸甲酯互穿网络的阻尼性能及相态

引言聚合物互穿网络体系由于在其形成过程中产生特殊的物理拓扑结构,使得该体系是一种永久缠结在一起的聚合物"合金"[1]。同时,由于构成该体系的聚合物组分往往不相容或部分相容,在其形成     

Synthesis and characterization of polyurethane/poly(vinylidene chloride) interpenetrating polymer networks

A series of polyurethane (PU)/poly(vinylidene chloride) (PVDC) interpenetrating polymer networks (IPNs) were synthesized through variations in the amounts of the prepolyurethane and vinylidene chloride monomer via sequential polymerization (80/20, 60/40, 50/50, 40/60, 30/70, and 20/80 PU/PVDC). The physicomechanical and optical properties of the IPNs were investigated. Thermogravimetric analysis (TGA) studies of the IPNs were performed to establish their thermal stability. TGA thermograms showed that the thermal degradation of the IPNs proceeded in three steps. Microcrystalline parameters, such as the crystal size and lattice disorder, of the PU/PVDC IPNs were estimated with wide‐angle X‐ray scattering. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1375–1381, 2007     

Second order non-linear optical interpenetrating polymer networks based on polyurethane or poly(methyl methacrylate) and epoxy polymer

Two interpenetrating polymer networks (IPNs), (one pseudo-IPN consisting of a linear polyurethane/epoxy-based polymer network and one full-IPN consisting of a poly(methyl methacrylate)/epoxy-based polymer network) have been synthesized and characterized. Both IPNs showed only one T_g; hence a homogeneous phase morphology is suggested. The second-order non-linear optical coefficients (d₃₃) of the pseudo-IPN and the full-IPN were measured and found to be 2.78 × 10⁻⁷ esu and 1.86 × 10⁷ esu, respectively. The study of temporal stability at room temperature and elevated temperature (120 °C) indicates that the full-IPN is more efficient at improving the orientational stability of the non-linear optical chromophores than the pseudo-IPN, because of the permanent entanglements of the two component networks in the full-IPN. © 1999 Society of Chemical Industry     

Latex interpenetrating polymer networks based on polyacrylates and poly(methyl methacrylate)

The effect of methacrylic acid (MAA) concentration in the polyacrylate seed on the formation of latex interpenetrating polymer networks (LIPNs) with poly(methyl methacrylate) (PMMA) as polymer II in the ratio of 65 : 35 (w/w) has been studied. LIPNs were prepared using three different seeds having the compositions of n-butyl acrylate (BA), methyl methacrylate (MMA), and tetra(ethylene glycol)dimethacrylate (TEGDM) in the ratio of 55 : 45 : 0.7 by weight and varying amounts of MAA (0, 2.5, and 6% by wt) at two different pH values (∼ 3.3 and 8.5). LIPNs prepared from seeds having MAA > 2.5% resulted in the formation of continuous films, whereas LIPNs without MAA in the seed yielded discontinuous films (i.e., films with many cracks). Characterization using differential scanning calorimetry (DSC) showed the presence of multiphase morphology in all the LIPNs, indicating better mixing of the two polymers. Another set of LIPNs using the seed of the composition BA : MMA : TEGDM in the ratio of 63 : 37 : 6 : 0.7 by wt, possessing a glass transition temperature of 0°C and PMMA as polymer II, was prepared at two different pH values, as mentioned earlier, and with two different initiators—namely, 2,2′-azobisisobutyronitrile (AIBN) and potassium persulfate (PPS)—for the polymerization of monomer II. The tensile strength and hardness of both the LIPNs processed at high pH (8.5) did not show significant differences, whereas the LIPNs prepared at low pH using the AIBN initiator showed an inverted core-shell morphology possessing very low hardness and tensile strength with high elongation. The PPS-initiated polymer showed core–shell morphology yielding film of poor strength. © 1996 John Wiley & Sons, Inc.     

High-resolution thermogravimetric analysis of polyurethane/poly(ethyl methacrylate) interpenetrating polymer networks

Thermal degradation of a series of polyurethane/poly(ethyl methacrylate) interpenetrating polymer networks and their constituent networks were studied by three modes of thermogravimetric analysis: the conventional method, the constant reaction rate method, and the dynamic rate technique. The best understanding of the degradation mechanism was achieved by the last method, which allows much better resolution of overlapping events. In addition, the weight losses correspond well with the results obtained from the constant reaction rate analysis, but are achieved in shorter times. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 287–295, 1998     

Synthesis and characterization of interpenetrating polymer networks from polyurethane and poly(ethylene glycol) diacrylate

Interpenetrating polymer networks (IPNs) combining polyurethane (PU) and poly(ethylene glycol) diacrylate (PEGDA) networks were prepared with simultaneous polymerization. PU was synthesized from biocompatible and biodegradable poly(ε-caprolactone) diol, and the hydroxyl group of poly(ethylene glycol) was substituted with a crosslinkable acrylate group. The effects of the PU/PEGDA compositions and the crosslink density of PU and PEGDA on the thermal properties, swelling ratio, surface energy, mechanical properties, and morphologies were investigated. The mechanical properties of PEGDA networks were improved by the presence of PU networks, particularly in the 75% PU/25% PEGDA IPNs. All PU/PEGDA IPNs showed a microphase-separated structure with cocontinuous morphology, as observed by atomic force microscopy, which was in agreement with the results of swelling ratio and dynamic mechanical thermal analysis measurements. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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     

Polyurethane–poly(methyl methacrylate) interpenetrating polymer networks. I. Synthesis,characterization, and preliminary blood compatibility studies

Simultaneous polyurethane–poly(methyl methacrylate) (PU–PMMA) interpenetrating polymer networks (IPNs) were synthesized with the PMMA polymerization initiated at room temperature. Transparent IPNs with better miscibility and synergism of mechanical properties were obtained. Dynamic mechanical analysis data indicated that up to 30% PMMA can be incorporated into PU networks without substantial phase separation. The PU–PMMA 90/10 IPNs elicit less than 2% hemolysis, suggesting that these materials could be used as blood contacting materials. © 1996 John Wiley & Sons, Inc.     

Room-temperature kinetics of castor-oil-based polyurethane/poly(2-hydroxyethyl methacrylate) interpenetrating polymer networks

The kinetics aspects of the formation of castor-oil-based polyurethane/poly(2-hydroxyethyl methacrylate) interpenetrating polymer networks (IPNs) were studied. The effect of parameters such as the polyurethane content, the activator, and acrylic cross-linker on the kinetics of formation of IPN networks was examined at room temperature. The formation of the individual networks, polyurethane, poly(2-hydroxethyl methacrylate), and their IPNs, was studied by measuring the decrease of absorbance of characteristic absorption peak of each system using IR spectroscopy. © 1994 John Wiley & Sons, Inc.     

Transition behaviour of polyurethane-poly(methyl methacrylate) interpenetrating polymer networks

The transition behaviour of polyurethane-poly(methyl methacrylate) interpenetrating polymer networks (PUR/PAc IPN's) was studied by means of differential scanning calorimetry (d.s.c.), dynamic mechanical spectroscopy (d.m.s.) and thermally stimulated depolarization (t.s.d.). Instead of a sharp discontinuity in heat capacity, as for the individual networks, a very broad change is observed by calorimetry and some intermediate changes in heat capacity appear too. D.m.s. yields only two peaks which show a marked inward shift, with an important damping and broadening, as compared to the individual networks. Some preliminary results obtained by t.s.d. confirm these findings. It can be concluded that PUR/PAc IPN's are phase separated, but that the mutual miscibility of both components is enhanced by the special mode of combining them, namely interpenetration. When the second component is not crosslinked, phases appear to be less entangled. Previous results on physical and mechanical properties corroborate these conclusions.     

Fabrication and apparent kinetic study of poly(methyl methacrylate)/poly(octyl acrylate) and poly(octyl acrylate)/poly(methyl methacrylate) latex interpenetrating polymer networks

Two latex interpenetrating polymer networks (LIPNs) were synthesized with methyl methacrylate (MMA) and octyl acrylate (OA) as monomers, respectively. The apparent kinetics of polymerization for the LIPNs was studied. This demonstrates that network II does not have a nucleus formation stage. The monomers of network II were diffused into the latex particles of network I and then formed network II by in situ polymerization. It indicates that the polymerization of network I obeys the classical kinetic rules of emulsion polymerization. But the polymerization of network II only appears a constant‐rate stage and a decreasing‐rate stage. The apparent activation energies (E_a) of network I and network II of PMMA/POA were calculated according to the Arrhenius equation. The E_a values of POA as network I (62 kJ/mol) is similar to that of POA as network II PMMA/POA (60 kJ/mol). However, the E_a value of PMMA as network II POA/PMMA (105kJ/mol) is higher than that of PMMA as network I (61 kJ/mol). Results show that the E_a value of the network II polymerization is related to the properties of its seed latex. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermomechanical properties and morphology of interpenetrating polymer networks of polyurethane–poly(methyl methacrylate)

Interpenetrating networks (IPNs) of polybutadiene‐based polyurethane (PU) and poly(methyl methacrylate) (PMMA) were synthesized. The effect of the incorporation of 2% glycidyl methacrylate (GMA) and 2‐hydroxyethyl methacrylate (2‐HEMA) on the thermal, mechanical, and morphological properties of IPNs was investigated. Both 2‐HEMA and GMA led to improvements in these properties. However, 2‐HEMA‐containing IPNs showed somewhat better tensile strength, elongation, and damping characteristics. The morphology of IPNs containing 2‐HEMA showed better mixing of the components. The improvement in the properties was observed for up to 40% PMMA in the IPNs. Differential scanning calorimetry thermograms showed the presence of three glass transitions. The third glass‐transition temperature was explained by possible grafting of methyl methacrylate onto PU. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1576–1585, 2002     

Semi‐ and full‐interpenetrating polymer networks based on polyurethane produced from canola oil and poly(methyl methacrylate)

Semi‐ and full‐interpenetrating polymer networks (IPNs) were prepared using polyurethane (PUR) produced from a canola oil‐based polyol with primary terminal functional groups and poly(methyl methacrylate) (PMMA). The properties of the material were studied and compared using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and tensile measurements. The morphology of the IPNs was investigated using atomic force microscopy (AFM). Semi‐IPNs demonstrated different thermal mechanical properties, mechanical properties, phase behavior, and morphology from full IPNs. Both types of IPNs studied are two‐phase systems with incomplete phase separation. However, the extent of phase separation is significantly more advanced in the semi‐IPNs compared with the full IPNs. All the semi‐IPNs exhibited higher values of elongation at break for all proportions of acrylate to polyurethane compared with the corresponding full IPNs. These differences are mainly due to the fact that in the case of semi‐IPNs, one of the constituting polymers remains linear, so that it exhibits a loosely packed network and relatively high mobility, whereas in the case of full IPNs, there is a higher degree of crosslinking, which restricts the mobility of the chains. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polyurethane-poly(methyl methacrylate) interpenetrating polymer networks: Some mechanical properties

The mechanical behavior of polyurethane-poly(methyl methacrylate) interpenetrating polymer networks (PUR/PAc IPN's) was investigated. Stress-strain and impact resistance measurements were made on IPN's with a variable PUR content. The effect of the degree of crosslinking of each network on the mechanical properties was also studied. It appears that only the ultimate elongation varies largely upon changing the crosslink degree. The results are interpreted in terms of the contribution of each network to the mechanical behavior, but also by the interpenetration of both components and by the phase continuity of the PAc network.     

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.     

Synthesis and characterization of polypropylene-based polymer hybrids linking poly(methyl methacrylate) and poly(2-hydroxyethyl methacrylate)

Isotactic polypropylene-based polymer hybrids linking poly(methyl methacrylate) (PMMA) and poly(2-hydroxyethyl methacrylate) (PHEMA) were successfully synthesized by a graft copolymerization from maleic anhydride-modified polypropylene (PP-MAH). PP-MAH reacted with ethanolamine to produce a hydroxyl group containing polypropylene (PP-OH) and the thus obtained PP-OH was treated with 2-bromoisobutyryl bromide and converted to a 2-bromoisobutyryl group containing polypropylene (PP-Br). The metal-catalyzed radical polymerization of MMA with PP-Br was performed using a copper catalyst system in o-xylene solution at 100 °C to give the PP-based polymer hybrids linking PMMA segments (PP-PMMA hybrids). Thus obtained PP-PMMA hybrids demonstrated higher melting temperature than PP-Br and microphase-separation morphology at the nanometer level owing to the chemical linkage between both segments. On the other hand, the polymer hybrids linking PHEMA segment (PP-PHEMA hybrids) were also obtained by the radical polymerization of HEMA with PP-Br in o-xylene slurry at 25 °C. TEM observation suggested that the polymerization mainly initiated on the surface of the PP-Br powder, led to the peculiar core-shell-like morphology. These PP-PHEMA hybrid powders showed a good affinity with water due to the hydrophilicity of the PHEMA segments.     

Simultaneous interpenetrating networks of a polyurethane and poly(methyl methacrylate). I. Metastable phase diagrams

Any simultaneous interpenetrating network (SIN) synthesis contains three key events. These are gelation of polymer I, gelation of polymer II, and phase separation of polymer I from polymer II. Metastable phase diagrams of SINs are developed, in which the time occurrence of these three events is represented. A polyurethane/poly(methyl methacrylate) (PU/PMMA) system was chosen as a model. Polymerization kinetics were followed in situ for both PU and PMMA using Fourier Transform Infrared Spectroscopy (FTIR) with the aid of a heated demountable cell. Glass transitions of fully cured samples were determined by dynamic mechanical spectroscopy (DMS) and differential scanning calorimetry (DSC). Phase separation was determined by the onset of turbidity, and gelation of the first gelling polymer was determined by the sudden resistance of the system to flow. As a result, a metastable phase diagram was constructed for the four-component SIN system (the two monomers and their respective polymers) as a tetrahedron in three dimensions with the two monomers and two polymers at the four apexes. Phase separation and gelations of the two polymers are indicated by various surfaces. These surfaces intersect at lines and curves, representing unique conditions of an SIN synthesis, e.g., simultaneous gelation of both polymers, or simultaneous phase separation and gelation of polymer I, etc. These conditions are critical in terms of the development of the SIN morphology, dividing the reaction space into specific regions. Finally, it is shown how the tetrahedron diagram helps visualize the course of the three key events during SIN synthesis, and provides direction for controlling them. © 1995 John Wiley & Sons, Inc.     

Rheological,mechanical, and morphological studies of epoxy/poly(methyl methacrylate) semi‐interpenetrating polymer networks

Semi‐interpenetrating polymer networks (semi‐IPNs) of epoxy resin and poly(methyl methacrylate) (PMMA) were synthesized. Methyl methacrylate (MMA) was polymerized by free radical mechanism with azo‐bis‐isobutyronitrile in the presence of oligomeric epoxy resin (DGEBA), and hexahydrophthalic anhydride as crosslinking agent. The gelation and vitrification transitions during cure/polymerization processes have been examined using parallel‐plates rheological technique. From differential scanning calorimetry and rheological techniques, it was suggested that both curing and polymerization processes occur simultaneously. However, the gelation time was longer for the semi‐IPN than those observed for the cure of pure DGEBA or polymerization of MMA. The gelation time increased significantly when 5% of MMA was employed, suggesting a diluent effect of the monomer. Higher amount of MMA resulted in a decrease of gel time, probably because of the simultaneous polymerization of MMA during the curing process. Structural examination of the semi‐IPNs, using scanning electron microscopy, revealed phase separation in nanoscale size for semi‐IPNs containing PMMA at concentrations up to 15%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Synthesis and characterization of polyurethane/polybenzoxazine‐based interpenetrating polymer networks (IPNs)

Sequential interpenetrating polymer networks (IPNs), based on polyurethane and polybenzoxazine, were synthesized. Fourier Transform infrared spectrometry was employed to monitor the formation kinetics, which indicated that only physical bonding existed in the resulting IPNs. Morphological investigations revealed a lightly phase separation behaviour in all of the IPNs studied. © 2003 Society of Chemical Industry     

Kinetic modeling of simultaneous polycondensation and free radical polymerization for polyurethane/poly(methyl methacrylate) interpenetrating polymer network

A comprehensive kinetic Monte Carlo algorithm has been developed to investigate the formation process of a polyurethane/poly(methyl methacrylate) (PU/PMMA) interpenetrating polymer network (IPN), in which a component independent strategy is proposed to perform the simulation of simultaneous polycondensation and free radical polymerization. An empiric diffusion model based on the mass fraction of polymer is used to quantify the effect of diffusional limitations on MMA polymerization. Results show that the presence of acrylic monomers has little impact on the formation rate of PU, but the presence of the PU network can accelerate the polymerization of MMA. In addition, the effects of component mass ratio, acrylic cross-linker concentration, and [NCO]/[OH] ratio on the IPN formation kinetics are investigated based on the kinetic model. It is believed that the as-developed modeling strategy can be extended to other IPN systems and provide a better understanding of the interactions between chemically independent networks.