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Title: INDUCTION HEATING OF THERMOPLASTIC MATERIALS BY PARTICULATE HEATING PROMOTERS
Page Range: p.333-342
Author(s): Bayerl T; Schledjewski R; Mitschang P
File size: 635K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
Induction heating is a fast and selective heating method, which can also be applied to polymeric materials, even though these materials do not offer the required electrical or ferromagnetic properties. To compensate for this deficiency, polymeric matrixes (high density polyethylene and polyamide 6) were compounded with various ferromagnetic and electrically conductive particles. The experimental series included induction heating experiments of compounds with different particle materials and variable filler grades at two distinct frequency levels (430 kHz and 2500 kHz). A mechanical characterisation of the compounds was performed to identify the influence of the particles on matrix properties. The heating experiments showed a significant temperature rise of the particle doped materials, when they were exposed to an alternating magnetic field. The temperature rise was observed with plates as well as with pellets. The heating effect was found to be dependent on the frequency and the particle material. The best results were obtained from ferromagnetic particles like iron and magnetite, whereas for example non-ferromagnetic carbon black could only be activated in pellet-shape at high magnetic field strength. To reach the melting temperature of the polymer within a maximum time frame of three minutes, the filler content of specific particles could be as low as 5 wt.%. The mechanical properties of the materials, such as tensile strength and stiffness were influenced only marginally, while the impact strength was reduced by the particles by up to 25%. 20 Refs.

Title: EFFECTS OF FUNCTIONALISATION ON CURING AND DECOMPOSITION BEHAVIOUR OF EPOXY-MWCNT NANOCOMPOSITES
Page Range: p.343-352
Author(s): Theodore M; Mahesh Hosur; Thomas J; Shaik Jeelani
File size: 642K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
Cure kinetics and decomposition behaviour of a two part epoxy resin system, Epon 862, reinforced with 1 wt.% unmodified, oxidised (MWCNT-COOH) and fluorinated (MWCNT-F) multi-walled carbon nanotubes have been studied through dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) at different conversion levels. Functionalised MWCNTs have disturbed the curing/decomposition behaviour, crosslink density, and the interactions between individual phases in the composite systems thus altering cure kinetics parameters like degree of conversion, activation energy, rate of reaction, enthalpy change, percentage conversion, which were determined using Arrhenius theory. 29 Refs.

Title: COMPARISON OF POLYIMIDE COMPOSITES WITH NON-COVALENT MODIFIED AND ACID MODIFIED MULTI-WALL CARBON NANOTUBE
Page Range: p.353-358
Author(s): Shang-Chih Chou; Yao-Yi Cheng
File size: 378K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
In this study, it was attempted to increase the electrical conductivity of polyimide (PI) by adding multi-wall carbon nanotubes (MWNT), mainly because the high aspect ratio carbon nanotubes can reduce resistance and enhance antistatic ability to meet electrostatic charge (ESC) criteria of polymer hybrid films. MWNT were modified successfully with a sodium salt of 6-aminohexanoic acid (Na-AHA), which has been verified by FTIR and TEM observations. During the blending process, the PI/MWNT composites thus produced were compared with unmodified MWNT to study the miscibility and interaction among the components. The homogeneous dispersion of the non-covalently modified MWNT (Na-AHA-CNT) promoted the thermal and electrical conductivity properties of PI composite films. The results are compared with those of PI composites with acid modified and unmodified MWNT. 30 Refs.

Title: EFFECT OF THE EXTRUSION PROCESS ON THE MORPHOLOGY AND ELECTRICAL CONDUCTIVITY OF INJECTION-MOULDED POLYPROPYLENE/HDPE/CARBON BLACK COMPOSITES
Page Range: p.359-366
Author(s): Zheng-Ying Liu; Yong-Juan Gao; Chao-Lu Yin; Shi-Lin Huang; Ming-Bo Yang
File size: 465K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
In this work, isotactic polypropylene (iPP)/high density polyethylene (HDPE) composites filled with carbon black (CB) were prepared by the mild compounding method and the common melt-mixing method. The selective distribution of CB particles in the immiscible iPP/PE blends was determined by the interfacial tensions, but the morphologies of the polyblends strongly depended on the compounding method. The mild compounding method strongly affected PE phases to form triple phase morphology in the composites, which inhibited effective conductivity network formation in the low CB content range. A skin-core structure of the iPP/HDPE/CB composite, prepared by the common melt-mixing process, was present when an effective conductivity network was obtained, and a co-continuous structure of the iPP/HDPE matrix is not necessary. 28 Refs.

Title: WELL-ALIGNED ZNO NANOTUBE/POLYANILINE PHOTOCATALYSTS FOR ENHANCED PHOTOCATALYTIC PERFORMANCES
Page Range: p.367-376
Author(s): Lin Lin; Qingsheng Wu
File size: 449K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
A well-aligned ZnO nanotube array has been successfully synthesised without depositing a layer of ZnO seeds, for the first time, on a glass substrate by a hydrothermal reaction. Subsequently, the oriented ZnO nanotube array was integrated with polyaniline (PANi) to form hybrid ZnO nanotube/PANi photocatalysts, which showed excellent photocatalytic activity for the photodegradation of Rhodamine B (RB). It was found that the photocatalytic performance under ultraviolet and visible light irradiation depended on the doping level of PANi. An investigation of photodegradation kinetics of RB indicated that the photocatalytic process showed first-order kinetics. The photodegradation mechanisms of RB dye under ultraviolet and visible light irradiation were also investigated. 42 Refs.

Title: IMPROVED CONDUCTIVITY OF POLYSACCHARIDE-CO-POLYACRYLATE/POLYANILINE CONDUCTING HYDROGELS
Page Range: p.377-386
Author(s): Lin Lin; Qingsheng Wu
File size: 447K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
In this article, three families of polysaccharide-co-polyacrylate copolymer hydrogels were synthesised by free radical polymerisation. The water absorbencies of the starch-co-polyacrylate, alginate-co-polyacrylate and chitosan-co-polyacrylate hydrogels were 1170, 1190 and 1350 g/g, respectively. The influences of crosslinker, initiator, neutralisation degree, monomer concentration and the polysaccharide dosage on the water absorbency of the hydrogels were thoroughly investigated. The molecular structures, thermal stability and morphology of the copolymer hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). To improve the conductivity, polysaccharide-co-polyacrylate/polyaniline conducting hydrogels with interpenetrating network structures were produced by in-situ polyaniline of aniline based on the high water absorbency of the copolymer hydrogels. The novel conducting hydrogels present good electrical and electrochemical behaviour, which makes them potentially useful in supercapacitors, biosensors, bioelectronics, solar cells and memory devices. 23 Refs.

Title: INSTABILITY OF THE PERFORMANCES OF FRP COMPOSITES IMPLEMENTED IN CIVIL ENGINEERING ENVIRONMENT: EXPERIMENTAL STUDY AND DURABILITY IMPLICATIONS
Page Range: p.387-398
Author(s): Marouani S; Curtil L; Hamelin P
File size: 440K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
Various aspects related to the durability of Fibre Reinforced Polymer (FRP) composites used in the rehabilitation, repair and strengthening of existing concrete structures were studied as a function of cure behaviour. The performance of these FRP-composites containing thermoset matrix and implemented under civil engineering conditions, is unstable and their properties will change over time due to their partial cure. The present work attempts to raise awareness about the characteristic changes of FRP-composites materials immediately after their ambient cure, while emphasizing the implication of such phenomena on the durability. Both glass transition temperature Tg and mechanical characterisation tests were performed to identify the effects of curing on thermorheological and mechanical stability of the composites immediately after the implementation. The experimental results indicate that overall composite performance was sensitive to the cure conditions. The implication of this sensitivity on the durability of FRP-composites was addressed and clearly identified through accelerated and natural exposure tests which reflected the civil engineering environment. 46 Refs.

Title: FLAME RETARDANCY AND NON-ISOTHERMAL CRYSTALLIZATION BEHAVIOUR OF PET/TIO2 NANOCOMPOSITES
Page Range: p.399-406
Author(s): Jianjun Zhang; Quan Ji; Xiuhong Shen; Yanzhi Xia; Liwen Tan; Fengjun Wang; Qingshan Kong
File size: 392K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
Titanium dioxide particles (TiO2) have been melt-compounded with poly(ethylene terephthalate) (PET) by using a twin-screw extruder to prepare PET/TiO2 nanocomposites. The flame retardancy and non-isothermal crystallisation behaviour of PET and PET/TiO2 nanocomposites have been studied using several techniques. The effects of TiO2 on the combustion behaviour of PET/TiO2 nanocomposites were analyzed by CONE and SEM. The results showed that the HRR, THR and TSR of nanocomposites was reduced significantly. The char residues were examined using scanning electron microscopy, indicating that TiO2 addition produced consistent and compact char crusts. The non-isothermal crystallisation behaviour of PET and PET/TiO2 were investigated by differential scanning calorimetry (DSC). Meanwhile, the kinetics of non-isothermal crystallisation was analyzed by the Mo Zhishen method. Both results showed that the TiO2 in PET acted as an effective nucleation agent. Not only was the crystallisation rate of composites obtained higher than that of the neat PET, but also the crystallisation time of the composites obtained was shorter than that of the neat PET. The presence of TiO2 changed the mechanism of the nucleation and accelerated the rate of PET crystallisation. 15 Refs.

Title: ENHANCED IONIC CONDUCTIVITY OF COMPOSITE PVA-NAFION ELECTROLYTE CONTAINING IONIC LIQUID BY ADDITION OF HYDROXYAPATITE PARTICLE
Page Range: p.407-410
Author(s): Zhiying Li; Xin Zhang; Changli Zhou; Danzi Sun
File size: 215K
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Journal: Polymers and Polymer Composites
Issue Year: ppc
Volume: 20
Issue No: No.4

Abstract
Composite electrolyte comprising hydroxyapatite (HAp) filler and 1-butyl-3-methyl -imidazolium bis(fluoromethane sulphonyl)imide (BMImTFSI) room temperature ionic liquid (RTIL) in poly(vinyl alcohol) (PVA) combined with Nafion matrix has been prepared. The polymer matrix was composed of PVA and Nafion providing the proton conductivity, BMImTFSI was used as both ionic source and plasticizer; HAp filler enhanced the ionic conductivity and thermal stability in this system. The electrolyte with HAp at the 20 wt.% showed the highest ionic conductivity of 1.2i10-3 S cm-1 at room temperature and 96% relative humidity. 8 Refs.

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