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Hyperbranched epoxy resin (HTDE) has relatively low viscosity and high molecular mass and holds great promise as a functional additive for enhancing the strength and toughness of thermosetting resins. In this work, the curing and thermal degradation kinetics of HTDE/diglycidyl ether of bisphenol-A epoxy (DGEBA) hybrid resin were studied in detail using differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) techniques by Coats–Redfern model. The effect of molecular mass or generation and content of HTME on the activation energy, reaction order, and curing time were discussed; the results indicated that HTDE could accelerate the curing speed and reduce the activation energy and reaction order of the curing reaction. [ABSTRACT FROM AUTHOR]

In this article, the organically modified clay (organoclay) was prepared by treating Na-montmorillonite with alkylammonium ions through a solid state method. Polypropylene (PP)/organoclay nanocomposites were prepared by melt intercalation. X-Ray Diffraction (XRD) and Transmission Election Microscopy (TEM) indicated that PP chains could intercalate into the gallery of organically modified clay to form the exfoliated PP/organoclay nanocomposites. The crystallization peak temperature of PP/organoclay nanocomposites was higher than that of neat PP by Differential Scanning Calorimetry (DSC). According to XRD, the addition of organoclay did not change the crystal structure of PP. Thermalgravimetric analysis showed that the thermal decomposition temperature of PP/organoclay nanocomposite was higher than that of PP. A mechanical properties test indicated that the impact strength of PP/organoclay nanocomposites were better than that of neat PP when the organoclay content was below 7 wt%. [ABSTRACT FROM AUTHOR]

A method of chemical modification in situ of ethylene-propylene-diene rubber (EPDM) filled with carbon black was studied. A bifunctional monomer, glycidyl methacrylate (GMA), was used as the modifier to improve the dispersibility of carbon black in the rubber and to enhance the mechanical properties of EPDM vulcanizates. The effects of GMA on the structure and properties of EPDM vulcanizates such as determination of cross-linking density and vulcanizing properties as well as mechanical properties were investigated by FT-IR, SEM, and DMTA. The results showed the addition of GMA into carbon black filled EPDM compounds could remarkably improve the mechanical properties of the vulcanizates. The optimum content of GMA was about 5.0 phr when the content of carbon black was 50 phr. The reason for improvement of the mechanical properties might be attributed to the chemical combinations between rubber macromolecular chains and carbon black surfaces by GMA. The action of GMA was similar to a cocuring agent and a coupling agent. [ABSTRACT FROM AUTHOR]

Halloysite nanotubes (HNTs) are novel 1D natural nanomaterials with predominantly hollow tubular nanostructures and high aspect ratios. Due to their high mechanical strength, thermal stability, biocompatibility, and abundance, HNTs have a number of exciting potential applications in polymer nanocomposites. In this article, we review the recent progress toward the development of HNTs-polymer nanocomposites, while paying particular attention to interfacial interactions of the nanocomposites. The characteristics of the HNTs relative to the formation of the polymer nanocomposites are summarized first. The covalent or non-covalent functionalization methods for HNTs and various fabrication approaches for HNTs-polymer nanocomposites are introduced afterward. Polymer nanocomposites reinforced with HNTs possess highly increased tensile and flexural strength, elastic moduli, and improved toughness. HNTs-polymer nanocomposites also exhibit elevated thermal resistance, flame retardance and unique crystallization behavior. Due to the tubular microstructure and the biocompatibility of HNTs, HNTs-polymer nanocomposites have demonstrated good drug encapsulation and sustained release abilities, gaining them extensive use as tissue engineering scaffolds and drug carriers. Finally, we summarize the characteristics of HNTs-polymer nanocomposites and predict for the development of the potential applications in high-performance composites for aircraft/automobile industries, environmental protection, and biomaterials. [ABSTRACT FROM AUTHOR]

The nanocomposites of natural rubber (NR) and organoclay with unsaturated carbon-carbon double bonds (C=C) on interlayer surfaces (USMMT) are prepared by the grafting and intercalating method in latex in the presence of butyl acrylate (BA) monomer. The conversion, grafting efficiency, and grafting percentage of BA onto NR and USMMT are determined. The structure and morphology of the nanocomposites are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmitted electron microscopy (TEM), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and swelling experiments. The mechanical properties of the nanocomposites are measured. The results show that graft copolymerization of BA monomer onto NR molecular chains can take place with high conversion, grafting percentage, and grafting efficiency. At the same time, BA can intercalate into the interlayer galleries of USMMT and polymerize in situ together with C=C bonds on the interlayer surfaces. As a result, the interlayer spacing of organaclay is increased and the interfacial combination between the silicate layers and rubber is strengthened. The results of XRD and TEM demonstrate the formation of the nanocomposites of NR-M-USMMT. The glass transition temperatures of the nanocomposites are higher than that of the NR vulcanizate. The mechanical properties of the nanocomposites are remarkably improved compared with those of the NR and NR-USMMT vulcanizate. [ABSTRACT FROM AUTHOR]

The scrap rubber powder (SRP) could be compression moulded to form elastomer via in situ interfacial reactions. In this study, SRP/NR (85/15) blends with good performance could be prepared by incorporating a little amount (lower than 5 phr of SRP and NR) of m-phenyl bismaleimide (BMI) in the compositions. The mechanical properties and the interface of SRP/NR (85/15, w/w) blends (base blend) were investigated. The results showed that the processing temperature, time, and BMI content have significant effects on the mechanical properties of the blends. The optimum BMI content and processing condition were determined as 5 wt.% and 180 ○C/10 min. The mechanical properties, especially the elongation at break, of the elastomers could be improved further by ultraviolet (UV) exposure. With UV exposure, the tensile strength, elongation at break and tear strength of the modified base blend were determined as 10.4 MPa, 260% and 24 KN/m respectively. The FTIR results indicated that the BMI could be grafted onto the SRP surface under UV exposure. The composition with UV exposure had more uniform dispersion of the BMI and improved interfacial adhesion. The glass transition temperature ( Tg) of the blends was increased by increasing the processing temperature, processing time or the introduction of UV exposure. [ABSTRACT FROM AUTHOR]

We reported newly prepared functionalized nanoparticles (RT@MS) using mesporous silica (MS) with antioxidant intermediate 4-aminodiphenylamine (RT) via the linkage of KH-560. RT@MS was used as a nanofiller to fabricate styrene--butadiene rubber (SBR) composites. Under the condition of equal antioxidant and filler components, functionalized mesoporous silica can greatly enhance the mechanical properties of SBR owing to the uniform dispersion and strong interfacial interaction between SBR and RT@MS. Besides, the antiaging behavior of SBR/RT@MS composites was systematically evaluated by thermal oxidation exothermic enthalpies and oxidation induction time before and after solvent extraction. The results indicated that RT@MS showed much better thermal and oxidative stabilities and longer service life than the most commonly used antioxidant N-isopropyl-N'-phenyl-4-phenylenediamine in SBR due to the improved migration resistance of immobilized RT. [ABSTRACT FROM AUTHOR]

To enhance the interfacial interaction between rubber and hybrid nanofiller (HS) consisting of halloysite nanotubes and silica, and simultaneously prevent migration and volatilization of rubber additives, commercial vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfenamide (CZ) was chemically grafted onto HS to obtain a functionalized nanofiller (HS-s-CZ). It was found that the grafted CZ molecules within an inorganic host structure have better efficiency to accelerate cross-linking reaction than free CZ molecules. In addition, HS-s-CZ could be evenly dispersed into styrene butadiene rubber (SBR) with further improved filler-rubber interaction compared with that between HS and SBR. Consequently, SBR/HS-s-CZ composites exhibited greater mechanical strength than SBR/HS composites containing equivalent accelerator component, showing 45% increase in tensile strength when the filler content was 40 phr. Potentially, this work offers a new design strategy for the surface modification of nanofiller and preparation of high-efficiency rubber additives, which may represent a new path for preparing high-performance elastomer composites. [ABSTRACT FROM AUTHOR]

To enhance the interfacial interaction between rubber and hybrid nanofiller (HS) consisting of halloysite nanotubes and silica, and simultaneously prevent migration and volatilization of rubber additives, commercial vulcanization accelerator N-cyclohexyl-2-benzothiazole sulfenamide (CZ) was chemically grafted onto HS to obtain a functionalized nanofiller (HS-s-CZ). It was found that the grafted CZ molecules within an inorganic host structure have better efficiency to accelerate cross-linking reaction than free CZ molecules. In addition, HS-s-CZ could be evenly dispersed into styrene butadiene rubber (SBR) with further improved filler-rubber interaction compared with that between HS and SBR. Consequently, SBR/HS-s-CZ composites exhibited greater mechanical strength than SBR/HS composites containing equivalent accelerator component, showing 45% increase in tensile strength when the filler content was 40 phr. Potentially, this work offers a new design strategy for the surface modification of nanofiller and preparation of high-efficiency rubber additives, which may represent a new path for preparing high-performance elastomer composites. [ABSTRACT FROM AUTHOR]

Rice husks are the fine crop residue used to prepare the industrial wood-like products by melt-blending with polymers. However, most wood-like products are highly filled with natural fibers in order to decrease the cost of the products, as it causes weak interfacial compatibility between the natural fibers and polymers. To successfully prepare a high performance wood-like product, the interfacial compatibility is the key problem that need to be solved. Moreover, the interfacial interactions at the gaps and voids around the natural fibers can enhance the interfacial compatibility of the composites. There is little research focusing on the interfacial interactions at these gaps and voids. In this paper, the multi-monomer graft copolymers of polyethylene (GPE) were used as the compatibilizers for the rice husk (RH) highly filled recycled polyethylene (rPE) composites. How the GPE affected the interfacial compatibility of the composites and the resulting mechanical properties, water resistance, thermal stability and rheological properties of rPE/RH composites were investigated. Results show that GPE could enhance the interfacial interactions of rPE/RH composites by infiltrating into the gaps and voids around RH. The strong interfacial interactions of the composites primarily came from the chemical reactions and physical interactions between RH and GPE. The mechanical properties, water resistance and thermal stability of the composites increased with the increase in GPE loadings. The preferable loadings of GPE were approximately at 8 phr. Meanwhile, GPE could improve the processing properties of the composites. [ABSTRACT FROM AUTHOR]

In this study, novel polyurethane/silica (PU/SiO2) hybrid materials, prepared without an external crosslinking agent, were developed via the chemical reaction between urethane groups of PU prepolymer and hydroxyl groups at the surfaces of silica. The added inorganic filler-silica thus played the dual roles not only inorganic chain extender but also reinforcing agent in the preparation of the hybrid. Two different blending methods, were compared with respect to the mechanical properties of the PU/SiO2 hybrid materials: stirring mixing and three-roller shear mixing. The hybridization mechanism was confirmed using Fourier-transform infrared spectroscopy (FT-IR), solid-state 29Si NMR spectroscopy and X-ray diffraction (XRD). The dispersion of silica particles in the PU matrix was investigated by scanning electron microscopy (SEM). Because of the shear effect of three-roller shear process, the size of the silica aggregates tended to be more uniform. The tensile strength and elongation at break of the PU/SiO2 hybrid were 51 MPa and 590%, respectively, which represent increases of fourfold and 39% compared to those of neat PU. The thermogravimetric analysis (TGA) results for the PU/SiO2 hybrids indicated greater thermal stabilities and lower decomposition rates after hybridization. This work contributes new insights into the preparation of high-performance PU/SiO2 hybrids. [ABSTRACT FROM AUTHOR]

Interfacial compatibility plays a key role in the performances of natural fiber-reinforced composites. The measures commonly used to improve the interfacial compatibility focus more on the addition of various compatibilizers than on the structural modification of the natural fiber. In this paper, an attempt was made to enlarge the interfacial interaction areas of the recycled polyethylene (rPE)/wood flour (WF) composites by steaming the WF. Multi-monomer graft copolymers of polyethylene (GPE) were used as compatibilizers for the composites. How the enlarged interfaces affected the morphology, mechanical properties, water resistance, thermal stability, and dynamic rheological properties of the rPE/WF composites was investigated. The steaming process was able to enlarge the voids of the WF and therefore activate more interfaces for interactions. It was found that the interfacial morphology of the composites was affected by the degree of interfacial compatibility of the composites and so was characterized by various distinctive blossom shapes having a variation of compositions. With the help of GPE, the steaming process was able to significantly improve the interfacial compatibility of the composites and therefore improve the mechanical properties, water resistance, thermal stability, and dynamic rheological properties of the composites. [ABSTRACT FROM AUTHOR]

We synthesized fully bio-based poly(propylene sebacate) using 1,3-propanediol, sebacic acid, and itaconic acid as raw materials. Another bio-based diacid, succinic acid, was introduced to tailor the flexibility of the copolyester. Accordingly, we obtained a series of crosslinkable copolyesters, covering from rigid plastics to soft elastomers. The rigid copolyesters could be used as shape memory polymers (SMPs). As the elastomeric copolyesters (noncrystalline ones and crystalline ones above Tm) are mechanically weak, zinc diacrylate (ZDA) was used as reinforcement to enhance the tensile strength and storage modulus in rubbery state. ZDA exhibited high reinforcing efficiency for the copolyesters. For instance, tensile strength and storage modulus above Tm of poly(propylene sebacate) (PPSS0) reinforced by ZDA (40 phr) increased by 368% and 745%, respectively. ZDA showed good compatibility with the copolyesters and polymerized ZDA particles dispersed uniformly in the matrices. Additionally, PPSS0/ZDA composites exhibited high shape fixity and shape recovery, making them suitable for fabricating biobased SMPs. [ABSTRACT FROM AUTHOR]

A novel intrauterine devices material, polyurethane/nano-copper (PU/NC) nanocomposite, was prepared. The structure, morphology, copper ion (Cu2+) release rate, and water absorption of PU/NC nanocomposites were investigated. The results indicated that the nanocoppers were uniformly dispersed in the matrix. The release rates of Cu2+ of PU/NC nanocomposites remained stable during the experimentation time. These results indicated that the PU/NC nanocomposites have a great potential to replace current commercial intrauterine devices materials. [ABSTRACT FROM AUTHOR]

The bisphenol AF/benzyltriphenylphosphonium chloride (BPP) vulcanization system is the most commonly used fluoroelastomer (FPM) vulcanization system. In this article, polyphenol hydroxy acrylic rubber (PHACM) was prepared through a two-step reaction: grafting polymerization and condensation. The properties of FPM/PHACM/acrylic rubber (ACM) blends including vulcanization properties, mechanical properties, aging properties, oil resistance and thermal properties were studied. The results of vulcanization properties show that under the bisphenol AF/BPP vulcanization system, the FPM can achieve covulcanization with PHACM without adding bisphenol AF and get longer scorch time than that of FPM with the same level of bisphenol AF, which means that FPM/PHACM/ACM blends have better processability and curing security. Furthermore, the blends show better mechanical properties and thermal stability. The results of differential scanning calorimeteric analysis show that the FPM and PHACM achieve co-cross-linking and have good compatibility. The glass transition temperature (Tg) of the blends has been reduced to −18.57°C, which is 8.33°C lower than that of pure FPM, when the content of blends is equal to 100/100. The scanning electron microscopy shows that PHACM can improve interfacial adhesion between the FPM and ACM. [ABSTRACT FROM PUBLISHER]

The ionic liquid, 1-butyl-3-methylimidazole hexafluorophosphate (BmimPF6), was utilized to modify carbon black (CB) via microwave (MW) irradiation. The conditions for the preparation of the modified CB (m-CB) were optimized. The reinforceability of the m-CB in styrene-butadiene rubber (SBR), butadiene rubber (BR) and nitrile rubber (NBR) composites were evaluated. The curing behaviour, morphology and tensile properties of the rubber/m-CB composites were studied and compared with those of composites filled with unmodified CB. Rubber/m-CB compounds showed a significant increase in the curing rate for a generated zinc complex with the alkylimidazoles. Compared with CB, m-CB exhibited a significantly improved reinforceability of the rubbers at lower filler loading, although the mechanical properties were changed slightly at higher filler loading. A possible mechanism was proposed, based on the molecular slippage theory in which the interfacial bonding, the filler loading and the chain flexibility of the rubber molecules were all considered. [ABSTRACT FROM AUTHOR]

In this study, a new trimethacrylate monomer α, α,α'-tri[4-(2′- hydroxy-30-methacryloyloxy-propoxy)phenyl]-1-ethyl-4-isopropylbenzene (α,α'- THMPEIB) with a molecular weight of 850 and a large molecular volume was designed and synthesized. The structure of monomer a,a,a0-THMPEIB was confirmed by FT-IR, ¹H NMR, and elemental analysis. Degree of double-bond conversion, volume shrinkage, water sorption and solubility, diffusion coefficient value, and flexure strength of α, α,α'-THMPEIB/tri(ethylene glycol) dimethacrylate- (TEGDMA) based resin were measured. 2,2-Bis[4-(2′-hydroxy-3′-methacryloyloxy- propoxy)-phenyl]-propane (bis-GMA)/TEGDMA monomer mixture was used as reference. The result showed that the α, α,α'-THMPEIB/TEGDMA-based resin had the lower double-bond conversion, polymerization shrinkage, and water solubility than bis-GMA/TEGDMA-based resin. Water sorption and diffusion coefficient value of α, α,α'-THMPEIB/TEGDMA-based resin were nearly the same as those of bis-GMA/TEGDMA-based resin. Flexural strength of α, α,α'-THMPEIB/TEGDMA-based resin was higher than that of bis-GMA/ TEGDMA-based resin. [ABSTRACT FROM AUTHOR]

Methacrylate resin-based sealers have attracted wide attention because of their easy handling, superior aesthetic qualities, good mechanical properties and excellent adhesive ability with dentin. 2,2-Bis[4-(2′-hydroxy-3′-methacryloyloxypropoxy)-phenyl]-propane (Bis-GMA) is the main component of the newly developed commercial root canal sealer 'Epiphany', which is one of the methacrylate resin-based sealers. In order to further reduce the polymerization volume shrinkage of Bis-GMA, 4,4′-(α-methylbenzylidene)-bis(2′-hydroxy-3′-methacryloyloxy-propoxy)benzene (4,4′-AMBHMB) with higher molecular weight and larger molecular volume was synthesized to replace Bis-GMA as one of the components of the root canal sealer used in this study. The structure of monomer 4,4′-AMBHMB was confirmed by FT-IR, 1H-NMR, mass spectrum and elemental analysis. The photopolymerization behavior of mixture of 4,4′-AMBHMB and triethylene glycol dimethacrylate (TEGDMA) was investigated by FT-IR. Degree of double bond conversion, volume shrinkage, water sorption and solubility, diffusion coefficient value, flexure strength and glass transition temperature of 4,4′-AMBHMB/TEGDMA system with a mass ratio of 50:50 were measured. A 50:50 Bis-GMA/TEGDMA formulation was used as reference. The results illustrated that 4,4′-AMBHMB/TEGDMA system had the same double bond conversion and water sorption with Bis-GMA/TEGDMA system. Polymerization shrinkage, water solubility and diffusion coefficient of 4,4′-AMBHMB/TEGDMA system were lower than that of the Bis-GMA/TEGDMA system, whereas the flexural strength and glass-transition temperature of 4,4′-AMBHMB/TEGDMA system were higher than that of the Bis-GMA/TEGDMA system. [ABSTRACT FROM AUTHOR]

Halloysite nanotubes (HNTs), a kind of naturally occurring silicates possessing typical fibular structure, were introduced to fabricate polypropylene (PP)/HNTs nanocomposites. The non-isothermal crystallization behaviors were investigated by differential scanning calorimetry (DSC) method according to different treatments. The results suggest, with the inclusion of HNTs in PP matrix, the nanocomposites crystallize at higher temperature regime, which are correlated with the heterogeneous nucleating effects of HNTs during the crystallization process of PP. The kinetics studies of crystallization show that PP nanocomposites possess faster crystallization process and higher activation energy due to the nucleating effect and hindrance effect of HNTs to the motion of PP chains. The polarized light microscopy (PLM) observations further show that HNTs serve as nucleation sites and accelerate the crystallization process. [ABSTRACT FROM AUTHOR]

Halloysite nanotubes (HNTs) were used to compound with linear low density polyethylene (LLDPE) to prepare composites with better mechanical properties and higher flame retardancy. The PE graft was used as interfacial modifier in the LLDPE/HNTs composites. HNTs were showed to be a promising reinforcing and flame retardant nano-filler for LLDPE. The mechanical properties and flame retardancy as well as thermal stability of the composites can be further enhanced by the addition of the graft copolymer. Morphological observation revealed that the graft copolymer could facilitate the dispersion of HNTs in LLDPE matrix and enhance the interfacial bonding. [ABSTRACT FROM AUTHOR]

The isothermal crystallization behavior of neat polypropylene (PP) and solid-phase graft copolymers of PP with maleic anhydride and methyl methacrylate (PPMM) were compared by differential scanning calorimetry. The Avrami equation and Hoffman theory were applied to describe the isothermal crystallization kinetics. The results show that the fitted isothermal crystallization parameters are similar to the experimental data, and suggest that the Avrami equation is suitable to describe the isothermal crystallization process of PP and PPMM. The grafted side chains on PP can change the nucleation and growth of crystallization. They caused a decrease in the apparent crystallization activation energy and lateral surface free energy, and an increase in the nucleation rate. This was attributed to the grafted side chains not only acting as nucleating agent but also hindering the motion of the molecular chains and reducing the growing rate of crystallization. [ABSTRACT FROM AUTHOR]

Natural occurred nanotubes, halloysite nanotubes, were modified by silane and incorporated into epoxy resin to form nanocomposites. The morphology of the nanocomposites was characterized by transmission electron microscopy (TEM). Dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were performed on the nanocomposites. Flexural property and coefficient of thermal expansion (CTE) of the nanocomposites were also determined. Comparing with the neat resin, about 40% increase in storage modulus at glassy state and 133% at rubbery state were achieved by incorporating 12 wt% modified HNTs into the epoxy matrix. In addition, the nanocomposites exhibited improved flexural strength, char yield and dimensional stability. TEM examination revealed a uniform dispersion of the nanotubes in the epoxy resin. The remarkably positive effects of the HNTs on the performance of the epoxy resin were correlated with the unique characteristics of the HNTs, the uniform dispersion and the possible interfacial reactions between the modified HNTs and the matrix. [ABSTRACT FROM AUTHOR]

The thermal decomposition and oxidation ageing behaviour of polypropylene (PP) and PP/halloysite nanotube (HNT) nanocomposites were studied. The kinetics of thermal decomposition were calculated by integral models. The thermal oxidation ageing was investigated by Fourier transform infrared spectroscopy (FTIR). The PP nanocomposites showed a higher activation energy of thermal decomposition than neat PP. Their surface treatment and lower HNT loading led to a higher activation energy of decomposition. Their improved thermal stability in nitrogen was attributed to entrapment of decomposition products at initial decomposition stage and to barrier effects. Nanocomposites made by using silane-modified HNT(m-HNT) and also those with lower quantities of (unsilanated) HNT showed improved resistance to thermo-oxidative ageing. The rate of thermo-oxidative ageing was correlated with the number of acidic sites and the volume of entrapped oxygen in the lumen of the HNT and in cavities. [ABSTRACT FROM AUTHOR]

Fabricating superhydrophobic surfaces via self-assembly of organic conjugated small molecules is realized by spray-drying the thiophene derivates organic solutions. Formation of microsized pores and arrayed nanofibers or nanorods on the surfaces is responsible for the superhydrophobicity of the coatings. This technique can be applied for fabrication of large area superhydrophobic surfaces with conjugated molecules on different substrates. [ABSTRACT FROM AUTHOR]

Many types of clay tend to absorb organics via electron transferring interactions between the clay and the organics. This may be utilized to design clay incorporated polymer composites with better interfacial properties. In the present paper, 2,5-bis(2-benzoxazolyl) thiophene (BBT), capable of donating electrons, is selected as the interfacial modifier for polypropylene (PP)/halloysite nanotube (HNTs) composites. The electron transfer between HNTs and BBT are confirmed. The mechanical properties and the unique morphology of the nanocomposites are examined. Formation of fibrils of BBT in the presence of HNTs is found in the nanocomposites. The chemical composition of the fibrils in the nanocomposites is found to be composed of largely BBT and a small amount of HNTs. The formation mechanism of BBT fibrils are elucidated to be the strong interactions between BBT and HNTs under melt shearing. The formation of the BBT fibrils leads to much higher crystallinity compared with previously reported PP nanocomposites. The nanocomposites with BBT show substantially increased tensile and flexural properties, which are attributed to the enhanced crystallinity of the nanocomposites. [ABSTRACT FROM AUTHOR]

A naturally occurred microtubullar silicate, halloysite nanotubes (HNTs), was co-cured with epoxy/cyanate ester resin to form organic-inorganic hybrids. The coefficient of thermal expansion (CTE) of the hybrids with low HNT concentration was found to be substantially lower than that of the plain cured resin. The moduli of the hybrids in the glassy state and rubbery state were significantly higher than those for the plain cured resin. The dispersion of HNTs in the resin matrix was very uniform as revealed by the transmission electron microscopy (TEM) results. The interfacial reactions between the HNTs and cyanate ester (CE) were revealed by the results of Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS). The substantially increased properties of the hybrids were attributed to the covalent bonding between the nanotubes and the matrix. [ABSTRACT FROM AUTHOR]