Papers by Keyword: Interpenetrating Polymer Networks

Abstract: Epoxy resin (EP) modified polyurethane prepolymer (PUP) was prepared by synthesizing prepolymer method, and then EP/PU interpenetrating polymer networks (IPN) composites was produced with better adhesive properties as the foam expands further. The effects of the process on graft reaction and spatial structure of EP/PU IPN composites was studied by FT-IR and scanning electron microscopy (SEM). And a study on the adhesive properties of polyurethane foams with different content of epoxy resins was done by adhesion strength test. The adhesive strength of the IPNs composites were significantly improved when the EP content was 50%. The thermal stability and the expansion ratio of EP/PU IPNs composites were reduced slightly. The modified IPN composites were expected to be used as the preparation of high viscosity and high dilatability of the special - purpose materials in future.

Abstract: Tribology behavior of Nanodiamond(ND) polyurethane(PU)/epoxy(EP) interpenetrating polymer networks hybrid materials were tested by friction wear testing machine. Results showed that when EP content was 30%, resultant PU/EP IPNs exhibited best wear resistance. For ND-PU/EP IPNs hybrids, when the ND addition was 0.2wt%, the best wear resistant ability was obtained. Under dry condition, the effect of wear parameters, such as rotational speed, load and central distance to friction and abrasion value were also investigated.

Abstract: Epoxy resin/polymethyl methacrylate(EP/PMMA,70/30) interpenetrating network composites containing various contents of dimethyl sulfoxide modified kaoline (EP/PMMA /K-DMSO) composites were prepared by a sequential polymeric technique and an in situ intercalation method. FTIR results showed that the epoxy ring opening reaction occurs, the formation of IPN structure of PMMA and EP has been created. The structure of composite material was characterized by scanning electronic microscopy (SEM). The result indicated that higher impact strength and lower tensile strength with increasing concentration of K-DMSO.

Abstract: Based on the molecule design and energy absorption theory of polymer macromolecule materials, we synthesized a kind of multicomponents interpenetrating polymer network(IPN) which composed of polyurethane(PU), epoxy(EP) and unsaturated polymer resin(UPR). In order to further widen the damping temperature region of polymer materials, we introduced the polydimethylsiloxane (PDMS) into polyurethane(PU). Because of solubility parameter difference between PDMS and PU, we synthesized PDMS modified PU by blocking and grafting PDMS chain into PU main chain firstly. Then, a serious of interpenetrating polymer networks (IPN) which composed of PDMS-PU, EP and UPR were designed and synthesized. The damping performance and microstructure were characterized by using the spectrum of dynamic mechanical thermal analysis (DMTA) and the scanning electron microscope(SEM) respectively. The tested result indicated that the multicomponents IPN which modified by PDMS has wider temperature range and higher damping loss factor, and the PDMS grafting PU/EP/UPR shows good damping performance and microphase compatibility specially.

Abstract: Interpenetrating polymer networks (IPNs) Poly(styrene-butadiene-styrene)/Poly(n-butyl methacrylate-b-methyl acrylate) (SBS/PBMA-b-PMA) was prepared by atom transfer radical polymerization (ATRP) and characterized by FT-IR, ¹H NMR and TEM. The TEM photos illustrated that SBS/PBMA-b-PMA formed an obvious core-shell structure, with cross-linked SBS/PBMA core and linear PMA shell. The compatibility of IPNs with PVC was studied using SEM and DSC instruments. The mixed polymers displayed one Tg (Tg=79.4°C, ΔTg=32.5°C) and showed good compatibility. The SEM fracture surface morphologies displayed partial feature of ductile fracture different form neat PVC.

Abstract: In the emulsion system, styrene, acrylate monomers and montmorillonite (Mt) were used to prepare interpenetrating polymer network/montmorillonite (IPN/Mt) nano-composite. X-ray diffraction (XRD), transmission electron microscopy (TEM) and dynamic mechanical analysis (DMA) were used to characterize the structure and damping property of the new material. Results of XRD and TEM showed that the layer structure of Mt was destroyed and Mt dispersed in the polymer matrix by single layer. The result of DMA indicated that the damping property of Styrene-Acrylic IPN/Mt was much better than that of Styrene-Acrylic IPN. Damping value of the Styrene-Acrylic IPN/Mt was well improved and the maximum of tanδ increased from 0.621 to 0.739, with a broad damping domain ranging from -41°C to 140+°C. All these findings indicated that styrene-acrylate IPN /Mt nano-composite of broad damping temperature range and high damping value was successfully prepared.

Abstract: The possibility that various silane treatments may enhance the corrosion resistance of a magnesium alloy AZ31 with silane-modified acrylate interpenetrating polymer network (IPN) coating has been investigated. Potentiodynamic electrochemical tests and neutral salt spray test were applied to evaluate the corrosion performance of the alloy. The results show that silane film improves corrosion resistance of the AZ31 alloy with and without IPN coating. The silane-modified IPN coatings improved more than 4 orders of magnitude of the corrosion resistance of the substrate.

Abstract: To obtain attractive properties, such as increased resistance to moisture absorption, low dielectric constant and low dielectric loss, the novel bismaleimide, viz. 2,7-bis(4-maleimidophenoxy) naphthalene (BMPN), and dicyanate ester, viz. 2,7-dihydroxynaphthalene dicyanate (DNCY), containing naphthalene ring and ether linkages, have been synthesized. The cure process of the blends including of 0.11mmol/mol Fe(AcAc)₃ and 2% nonylphenol is characterized by in-situ FTIR. The result obtained from in-situ FTIR spectra of cured resin illuminates that the cure reaction is homo-polymerized respectively at this condition for the mixtures of B1C1. Interlaced network patterns are seen obviously and no visible phase separation could be detected in the region for IPNs BT resin by SEM. The structure of IPNs can be formed for the blends of BMPN and DNCY containing 0.11 mmol/mol Fe(AcAc)₃ and 2% nonylphenol, which is tested by in-situ FTIR and SEM methods. The glass fiber reinforced composites for this blends are made and their properties are studied. This composites show good flexural property, low dielectric constants ( Dk ) and low moisture absorption.

Abstract: Epoxy/polyurethane interpenetrating polymer network coatings(EP/PU IPNs) modified by organic montmorillonite(oMMT)were prepared by interpenetrating polymer technology and in situ intercalative polymerization methods. TEM analysis showed that there is interaction between the oMMT and EP, PU phase, and the oMMT plays a role of "cross-linking point", changing the EP/PU matrix microstructure. Electrochemical analysis showed that oMMT and IPNs of EP and PU exhibits synergistic effect on improving anticorrosive properties of pure EP. When PU content is 30%, oMMT content is 3%, the EP/PU IPNs coatings has the best corrosion resistance.

Abstract: Interpenetrating polymer networks (IPNs) have been developed for many years leading to materials with controlled properties. When an electronic conducting polymer (ECP) is incorporated into an IPN, this one becomes a conducting IPN (CIPN). The synthetic pathway ensures a non homogeneous dispersion of the ECP through the IPN thickness of the material. The system is thus similar to a layered one with the advantage that the intimate combination of the three polymers needs no adhesive interface. The last step in making the CIPN into an actuator is to ensure the ionic conductivity by incorporation of an ionic salt. The highest ionic conductivity through the IPN matrix is necessary in order to ensure the best actuation. The chosen salt is an ionic liquid, i.e. 1-ethyl-3- methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI). Based on IPN architectures electrochemical actuators have been designed and actuation in open air has been characterized.