不同直链含量热塑性淀粉的制备及性能研究

利用转矩流变仪,以丙三醇为增塑剂对不同来源的淀粉进行改性制备热塑性淀粉（TPS）。采用X射线衍射仪（XRD）、热重分析仪（TG）、水接触角测量仪、傅里叶变换红外光谱仪（FTIR）和扫描电子显微镜（SEM）等对获得的热塑性淀粉进行了表征。结果表明,4种热塑性淀粉均含有颗粒状和颗粒状碎片,并且在热塑性木薯淀粉中所含比例更高;淀粉在增塑过程中达到稳态的扭矩依次为木薯淀粉（23 N·m）>玉米淀粉（21 N·m）>马铃薯淀粉（17.8 N·m）>蜡质玉米淀粉（15.2 N·m）,这与不同种类来源淀粉的直链淀粉比例差异直接相关;不同类型的淀粉与增塑剂形成氢键的能力存在差异,蜡质玉米淀粉的能力最强;4种热塑性淀粉的亲水性依次为热塑性木薯淀粉（75.9 °）>热塑性玉米淀粉（69.2 °）>热塑性马铃薯淀粉（67.9 °）>蜡质玉米淀粉（64.9 °）。     

Preparation and characterization of thermoplastic starch–kaolinite nanocomposite films

In this work, the thermoplastic starch–kaolinite (KAO) nanocomposite films were first prepared via solution‐casting method using chitosan‐modified KAO (CKAO) and Na⁺–KAO (NKAO). The structure was investigated by X‐ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy techniques. The results showed that the well‐dispersed KAO layers were delaminated in the starch matrix attesting to anexfoliated nanocomposite and formed strong interaction with starch molecules. According to thermogravimetric analysis, differential scanning calorimetric study, and water absorption testing, the starch–CKAO–urea nanocomposites have the greatest enhancements compared with those of starch–urea film and starch–NKAO–urea nanocomposites. These results provide the important information with using CKAO to obtain the exfoliated starch nanocomposites with high performance. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Physico‐mechanical properties of nano‐polystyrene‐decorated graphene oxide–epoxy composites

Nano‐polystyrene (nPS)‐decorated graphene oxide (GO) hybrid nanostructures were successfully synthesized using stepwise microemulsion polymerization, and characterized using Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), field‐emission scanning electron microscopy and transmission electron microscopy. XRD and FTIR spectra revealed the existence of a strong interaction between nPS and GO, which implied that the polymer chains were successfully grafted onto the surface of the GO. The nPS‐decorated GO hybrid nanostructures were compounded with epoxy using a hand lay‐up technique, and the effect of the nPS‐decorated GO on the mechanical, thermal and surface morphological properties of the epoxy matrix was investigated using a universal tensile machine, Izod impact tester, thermogravimetric analysis and contact angle measurements with a goniometer. It was observed that in the epoxy matrix, GO improved the compatibility. © 2017 Society of Chemical Industry     

Preparation and properties of poly(lactic acid)/lipophilized graphene oxide nanohybrids

Poly(lactic acid) (PLA)/lipophilized graphene oxide (LGO) nanohybrids were prepared using a solution blending method. Graphene oxide (GO) was synthesized using a modified Hummers method and then lipophilized by functionalization with alkylamines such as octylamine, dodecylamine or octadecylamine (ODA). PLA/GO nanohybrids were also prepared for comparison. Among the LGOs, ODA‐GO was chosen to produce the PLA/LGO nanohybrids because ODA‐GO exhibited obvious intercalation behavior and the best dispersibility in chloroform. The properties of the PLA/GO and PLA/LGO nanohybrids were investigated using scanning electron microscopy, wide‐angle X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, a universal testing machine, chemical resistance measurements and hydrolytic degradability analysis. The hydrophobic ODA‐GO was dispersed on the nanoscale within the PLA matrix and the resulting nanohybrids showed significantly higher chemical resistance and reduced hydrolytic degradation. © 2017 Society of Chemical Industry     

Preparation and properties of thermoplastic starch/montmorillonite nanocomposites using N,N‐bis(2‐hydroxyethyl)formamide as a new additive

N,N‐Bis(2‐hydroxyethyl)formamide (BHF) was synthesized efficiently and used as a new additive to prepare thermoplastic starch/montmorillonite (TPS/MMT) nanocomposites. Here, BHF acted as both plasticizer for TPS and swelling agent for MMT. The hydrogen bond interaction among BHF, starch, and MMT was proven by Fourier transform infrared (FTIR) spectroscopy. By scanning electron microscope (SEM), starch granules were completely disrupted. Atomic force microscopy demonstrated that partially exfoliated TPS/MMT nanocomposites were formed. The crystallinity of corn starch, MMT, BHF‐plasticized TPS (BTPS), and TPS/MMT nanocomposites was characterized by X‐ray diffraction (XRD), XRD demonstrated that partially intercalated TPS/MMT nanocomposites were formed. The water resistance of TPS/MMT nanocomposites increased compared with that of pure BTPS. Mechanical properties of BTPS and TPS/MMT nanocomposites were examined. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Effect of octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) functionalized graphene oxide on the mechanical,thermal, and hydrophobic properties of waterborne polyurethane composites

A novel graphene nanomaterial functionalized by octa(aminopropyl) polyhedral oligomeric silsesquioxane (OapPOSS) was synthesized and then confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), Raman spectroscopy, X‐ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy with energy‐dispersive X‐ray spectroscopy (SEM EDX), atomic force microscopy, and X‐ray diffraction. The obtained functionalized graphene (OapPOSS‐GO) was used to reinforce waterborne polyurethane (WPU) to obtain OapPOSS‐GO/WPU nanocomposites by in situ polymerization. The thermal, mechanical, and hydrophobic properties of nanocomposites as well as the dispersion behavior of OapPOSS‐GO in the polymer were investigated by TGA, a tensile testing machine, water contact angle tests, and field emission SEM, respectively. Compared with GO/WPU and OapPOSS/WPU composites, the strong interfacial interaction between OapPOSS‐GO and the WPU matrix facilitates a much better dispersion and load transfer from the WPU matrix to the OapPOSS‐GO. It was found that the tensile strength of the OapPOSS‐GO/WPU composite film with 0.20 wt % OapPOSS‐GO exhibited a 2.5‐fold increase in tensile strength, compared with neat WPU. Better thermal stability and hydrophobicity of nanocomposites were also achieved by the addition of OapPOSS‐GO. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44440.     

Effect of flake size on thermal properties of graphene oxide/poly(methyl methacrylate) composites prepared via in situ polymerization

The effect of graphene oxide (GO) flake size on thermal properties of GO/poly(methyl methacrylate) (GO/PMMA) composites prepared via in situ polymerization was investigated. Two styles of GO sheets were synthesized from different sizes of graphite powders by modified Hummers' method and GO/PMMA composites with GO of different sizes were prepared via in situ polymerization. Transmission electron microscopy verified that GO sheets produced from large graphite powders was obviously larger than that from small graphite powders. The similar number of layers and disorder degree of two types of GO sheets were proved by X‐ray diffraction and Raman, respectively. X‐ray diffraction and scanning electron microscopy results of GO/composites proved the homogenous dispersion of both two types of GO sheets in polymer matrix. Dynamic mechanical analysis and thermogravimetric analysis results showed that large GO sheets exhibit better improvement than small GO sheets in thermal properties of the composites. Compared with neat PMMA, the glass transition temperature and decomposition temperature of the composites with large GO sheets (0.20 wt %) were increased by 15.9 and 25.9 °C, respectively. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46290.     

Preparation of polyester resin/graphene oxide nanocomposite with improved mechanical strength

Graphene oxide (GO) has attracted huge scientific interest due to its unique physical and chemical properties as well as its wide‐scale applicability including facile synthesis and high yield. Here, we report preparation of nanocomposites based on GO and unsaturated polyester resin (PE). The synthesized samples were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and tensile strength measurements. A good dispersion of the GO sheets within the resin matrix was observed from the morphological analysis. A significant enhancement in mechanical properties of the PE/GO composites is obtained at low graphene loading. Around 76% improvement of tensile strength and 41% increase of Young's modulus of the composites are achieved at 3 wt % loading of GO. Thermal analysis of the composite showed a noticeable improvement in thermal stability in comparison to neat PE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and properties of fluorinated graphene oxide bisphenol a epoxy nanocomposites

This study thoroughly studied the implements of fluorosilane modified graphene oxide (GO) on the mechanical, thermal, and water absorption properties of the epoxy composites built up by specific content of modified GO. Fluorosilane graphene oxide (GOSiF) was analyzed using Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, X‐ray photoelectron spectroscopy, and X‐ray diffractometer. The epoxy composites tensile and bending modulus were increased by 11.46% and 62.25% with 0.1 and 0.5 wt% GOSiF loading, respectively. The good interfacial interaction was observed between epoxy matrix and GOSiF nanosheets under scanning electron microscopy. The thermal stability increases with GOSiF loading. Epoxy composite with 0.3 wt% GOSiF shows 5 °C increases in the T_10%. The residual weight raised by 58.67% with 0.3 wt% GOSiF content. The water absorption study revealed small water uptake was obtained for all GOSiF composites. With 0.3 wt% loading of GOSiF, the maximum water content drops from 4.97% for neat epoxy to 1.98%. POLYM. ENG. SCI., 59:1250–1257 2019. © 2019 Society of Plastics Engineers     

Nanocomposites from plasticized high‐amylopectin,normal and high‐amylose maize starches

Three types of maize starch with different amounts of amylose and amylopectin were used to prepare plasticized starch/clay nanocomposite films by casting. Studies by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) indicated that the intercalation/exfoliation of the plasticized starch molecules took place into the clay galleries for the three types of starch. However, the plasticized waxy starch molecules were the easiest of them all to be intercalated/exfoliated, which was reflected in the highest increment of the stress at peak of these nanocomposites. Moreover, the lowest water uptake was showed by the plasticized high‐amylose starch/clay nanocomposites. It was concluded that varying contents of amylose and amylopectin influenced the formation of intercalated/exfoliated clay structures and also affected the interactions of clay with water. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Effects of graphene oxide on the formation,structure and properties of bionanocomposite films made from wheat gluten with chitosan

Graphene oxide (GO) was combined with wheat gluten (WG) and chitosan (CS) to prepare bionanocomposite films using a casting method. The films were characterized using a variety of techniques, including scanning and transmission electron microscopies, atomic force microscopy, X‐ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, mechanical testing, water swelling, oxygen permeability and contact angle measurements, to determine the effects of GO on the formation, structure and properties of the bionanocomposites. Their formation and properties were found to be dependent on the mixing order of the three components. The added GO was found to strengthen the films, as well as to decrease water absorption and oxygen permeability. These effects were attributed to the good dispersion of GO in the WG/CS matrix enabled by hydrogen bonds. The decreased water absorption could be explained by the increased hydrophobicity. The notable improvement of the properties of the WG/CS films as a result of GO addition makes the films suitable as packaging materials. © 2016 Society of Chemical Industry     

Thermal and mechanical properties of liquid silicone rubber composites filled with functionalized graphene oxide

To improve the thermal and mechanical properties of liquid silicone rubber (LSR) for application, the graphene oxide (GO) was proposed to reinforce the LSR. The GO was functionalized with triethoxyvinylsilane (TEVS) by dehydration reaction to improve the dispersion and compatibility in the matrix. The structure of the functionalized graphene oxide (TEVS‐GO) was evaluated by Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectra, X‐ray diffraction (XRD), and energy dispersive X‐ray spectroscopy (EDX). It was found that the TEVS was successfully grafted on the surface of GO. The TEVS‐GO/LSR composites were prepared via in situ polymerization. The structure of the composites was verified by FTIR, XRD, and scanning electron microscopy (SEM). The thermal properties of the composites were characterized by TGA and thermal conductivity. The results showed that the 10% weight loss temperature (T₁₀) increased 16.0°C with only 0.3 wt % addition of TEVS‐GO and the thermal conductivity possessed a two‐fold increase, compared to the pure LSR. Furthermore, the mechanical properties were studied and results revealed that the TEVS‐GO/LSR composites with 0.3 wt % TEVS‐GO displayed a 2.3‐fold increase in tensile strength, a 2.79‐fold enhancement in tear strength, and a 1.97‐fold reinforcement in shear strength compared with the neat LSR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42582.     

Preparation of polyacrylonitrile/graphene oxide by in situ polymerization

Highly oriented molecular structure is essential for high‐performance carbon fibers. The addition of a small amount of graphene sheets may enhance the degree of molecular orientation of precursor fibers during spinning and stabilization by limiting the disorientation of the chain segments. Graphene sheets merge into the carbon fiber structure during carbonization. The structure and properties of polyacrylonitrile containing graphene oxide (GO) prepared by in situ polymerization were investigated. With increasing GO loading, the molecular weight of the polymer decreased gradually from 69 000 g mol^?1 for the sample without GO to 60 600 g mol^?1 for the sample with 2.5 wt% loading of GO. Scanning electron microscopy and X‐ray diffraction results indicated that GO was dispersed in single layers in the polymer matrix. The degree of crystallization of the polymer with 0.5 wt% GO was increased by 8%. Moreover, differential scanning calorimetry and thermogravimetric analysis showed that an appropriate amount of GO, e.g. 0.5 wt%, made the carbon yield of the polymer increase by 5.0 wt%, because the GO in the composite improved the intermolecular crosslinking reaction. Copyright © 2012 Society of Chemical Industry     

Latex co‐coagulation approach to fabrication of polyurethane/graphene nanocomposites with improved electrical conductivity,thermal conductivity,and barrier property

This study describes a simple and effective method of synthesis of a polyurethane/graphene nanocomposite. Cationic waterborne polyurethane (CWPU) was used as the polymer matrix, and graphene oxide (GO) as a starting nanofiller. The CWPU/GO nanocomposite was prepared by first mixing a CWPU emulsion with a GO colloidal dispersion. The positively charged CWPU latex particles were assembled on the surfaces of the negatively charged GO nanoplatelets through electrostatic interactions. Then, the CWPU/chemically reduced GO (RGO) was obtained by treating the CWPU/GO with hydrazine hydrate in DMF. The results of X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Raman analysis showed that the RGO nanoplatelets were well dispersed and exfoliated in the CWPU matrix. The electrical conductivity of the CWPU/RGO nanocomposite could reach 0.28 S m^?1, and the thermal conductivity was as high as 1.71 W m^?1 K^?1. The oxygen transmission rate (OTR) of the CWPU/RGO‐coated PET film was significantly decreased to 0.6 cm³ m^?2 day^?1, indicating a high oxygen barrier property. This remarkable improvement in the electrical and thermal conductivity and barrier property of the CWPU/RGO nanocomposite is attributed to the electrostatic interactions and the molecular‐level dispersion of RGO nanoplatelets in the CWPU matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43117.     

Microwave irradiation synthesis and characterization of RGO‐AgNPs/polystyrene nanocomposites

Polystyrene and reduced graphene oxide/silver (PSTY/RGO/AgNPs) nanocomposites were prepared via an in situ bulk polymerization method using two different preparation techniques. In the first approach, a mixture of silver nitrate, hydrazine hydrate, and polystyrene containing graphene oxide (PSTY/GO) were reduced by microwave irradiation (MWI) to obtain R‐(PSTY‐GO)/AgNPs nanocomposites. In the second approach, a mixture of the (RGO/AgNPs) nanocomposite, which was produced via MWI, and STY monomers were polymerized using an in situ bulk polymerization method to obtain PSTY‐RGO/AgNPs nanocomposites. The two nanocomposites were compared and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, high‐resolution transmission electron microscopy, Differential scanning calorimetry, and thermogravimetric analysis. The results indicate that the nanocomposites obtained using the first approach, which involved MWI, exhibited a better morphology and dispersion with enhanced thermal stability compared to the nanocomposites prepared without MWI. POLYM. COMPOS., 35:2318–2323, 2014. © 2014 Society of Plastics Engineers     

Synthesis of polythiophene/graphene oxide composites by interfacial polymerization and evaluation of their electrical and electrochemical properties

We report a new method for the synthesis of polythiophene (PTh)/graphene oxide (GO) nanocomposites by interfacial polymerization. Polymerization occurred at the interface of two immiscible solvents, i.e. n‐hexane containing thiophene and nitromethane containing GO and an initiator. Characterizations were done using Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and electrochemical and electrical conductivity measurements. Spectroscopic analyses showed successful incorporation of GO in the PTh matrix. Morphological analysis revealed good dispersion of GO sheets in the polymer matrix. The PTh/GO composites showed marked improvements in thermal stability and electrical conductivity (2.7 × 10^?4 S cm^?1) compared to pure PTh. The composites exhibited excellent electrochemical reversibility compared to pure PTh at a scan rate of 0.1 V s^?1. The composites were stable even up to 100 electrochemical cycles, indicating good cycle performance. The specific capacitance of the composites was calculated using cyclic voltammetry and was found to be 99 F g^?1. © 2014 Society of Chemical Industry     

Encapsulation of Cyclotetramethylenetetranitramine (HMX) by Electrostatically Self‐Assembled Graphene Oxide for Desensitization

To improve the safety of cyclotetramethylenetetranitramine (HMX) particles, a novel strategy was developed for the fabrication of graphene oxide encapsulated HMX (HMX@GO) by electrostatic self‐assembly between graphene oxide and HMX particles. The prepared samples were characterized by optical microscopy, scanning electron microscopy, Raman spectroscopy, X‐ray photon spectroscopy, thermogravimetry, differential scanning calorimetry and water contact angle tests. The results revealed that GO sheets were coated densely and homogeneously on the HMX particles in a HMX@GO composite at a low GO content of about 0.23 wt %. Compared with that of raw HMX, the impact sensitivity of the HMX@GO composite decreased from 100 % to 30 %, and the 50 % probability of required ignition energy (E₅₀) in the electrostatic spark sensitivity test increased from 0.66 J for HMX to 1.12 J for the HMX@GO composite, suggesting that the electrostatically self‐assembled GO coating layer could obviously enhance the safety of HMX.     

Effect of base‐deposited graphene oxide on the thermal stabilization of poly(vinyl chloride)

Graphene oxide was deposited in a base solution to form base‐deposited graphene oxide (bd‐GO) particles. The structure and properties of the bd‐GO particles were evaluated using transmission electron microscopy, powder X‐ray diffraction and X‐ray photoelectron, Fourier transform infrared, UV‐visible and fluorescence spectroscopies. The effect of the bd‐GO particles on the thermal stabilization of poly(vinyl chloride) (PVC) was investigated using the Congo red test and thermogravimetric analysis. The results showed that the thermal stability of PVC was greatly improved by the bd‐GO particles. Furthermore, this stabilization mechanism was investigated using UV‐visible spectroscopy and nitrogen adsorption–desorption isotherm analysis. It was found that the improvement of thermal stability was mainly related to the deactivation of thermally labile structural defects in the PVC chains by the carboxylate and alkoxide moieties of the basic groups in the bd‐GO particles, and the highly efficient adsorption of the bd‐GO particles with hydrogen chloride produced during PVC degradation. © 2015 Society of Chemical Industry     

Preparation and Characterization of Insensitive HMX/Graphene Oxide Composites

To improve the safety of HMX, a two‐dimensional (2D) graphene oxide (GO) was introduced to HMX by the solvent nonsolvent method. The morphology, composition, thermal decomposition characteristic were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), thermogravimetry (TG) and differential scanning calorimetry (DSC). Compared to the previous reports, GO sheets exhibited better desensitizing effect than [60]Fullerene and CNTs. When 2.0 wt‐% GO sheets were added, the impact sensitivity of raw HMX decreased from 100 to 10 %, and the friction sensitivity reduced from 100 to 32 %. The DSC results proved that GO sheets were compatible with HMX. In addition, by determining the thermal decomposition kinetic parameters of the samples, it was found that the activation energy (E_a) of HMX with 2.0 wt‐% GO increased by 23.5 kJ mol⁻¹, suggesting that GO sheets could improve the thermal stability of HMX.     

Layer‐structured poly(vinyl alcohol)/graphene oxide nanocomposites with improved thermal and mechanical properties

Layer‐structured poly(vinyl alcohol)/graphene oxide nanocomposites in the form of films are prepared by simple solution processing. The structure and properties of these nanocomposites are studied using X‐ray diffractions, scanning electron microscopy, Fourier‐transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The results indicate that graphene oxide is dispersed on a molecular scale and aligned in the poly(vinyl alcohol) matrix, and there exists strong interfacial interactions between both components, which are responsible for the significant improvement in the thermal and mechanical properties of the nanocomposites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011