Integral Procedural Decomposition Temperature Research Articles

Thermal and Electrical Transport Properties of o-Substituted Polyanilines Encapsulated with CuO Nanoparticles

Fabrication of substituted polyaniline nanocomposites with CuO results in hybrid materials with enhanced synergistic properties. Hence poly(2-chloroaniline)-composite-CuO, poly(2-chloroaniline)-composite-CuO/SDS, poly(2-methoxyaniline)-composite-CuO/SDS and poly(2-methylaniline)-composite-CuO/SDS nanocomposites were prepared chemically by in situ oxidative polymerization method. Characterization by a number of techniques such as FTIR, NMR and UV-visible spectroscopic methods, XRD and TEM are presented. The substituted polymers exhibited an appreciable interaction with the CuO (5 wt.%) nano fillers. Integral Procedural Decomposition Temperature (IPDT) and Oxidative Index(OI) calculations were done to establish the stability to heat. Thermal stability of the materials follows the trend p2ClAni-CuO-SDS > p2ClAni-CuO> p2MeAni-CuO-SDS> p2OMeAni-CuO-SDS. The electrical conductivities of poly(2-chloroaniline)-composite-CuO and poly(2-chloroaniline)-composite-CuO/SDS measured are 1.46 × 10-7 and 1.59 × 10-7 S cm-1, respectively and the presence of anionic surfactant does not change the electrical conductivity behaviour. The poly(2-methoxyaniline)/CuO-SDS and poly(2-methylaniline)/CuO-SDS exhibit an electrical conductivity of 1.68 × 10-6 and 1.24 × 10-6 S cm-1 respectively. The dielectric constant decreased with increase in frequency in the low frequency region due to electrical relaxation process. At low frequency there was a strong frequency dispersion of permittivity and above 2.5 Hz a frequency independent behavior was noted

Effects of two different agents, H3PO4 and NaCl, to increase the flame-retardant properties of cellulose fibers

After flame-retardant treatment by the two different agents, the thermal behaviors of Lyocell fibers are discussed. In this research, H3PO4 and NaCl reduced the degradation rate and increased the char yield of the Lyocell fibers, and also increased the limiting oxygen index with the char yield increased. After treatment, the integral procedure decomposition temperature and the activation energy of Lyocell fibers are significantly increased by various concentration factors. These phenomena were indicated by the dehydration, rearrangement, formation of carbonyl groups, the evolution of carbon monoxide and dioxide, and carbonaceous residue formation. These effects were indicating the slow pathway of flame retardancy for the Lyocell fibers and are attributed to the two different flame-retardant agent treatments.

Oxyfluorination of expanded graphite: improving the thermal properties of epoxy composites through interfacial interaction

To enhance the thermal properties of epoxy composites, expanded graphite (EG) was oxyfluorinated and embedded into epoxy resin as a reinforcement. The maximum thermal conductivity was obtained for epoxy composites with oxyfluorinated EG, representing a 62% increase compared to that of neat epoxy. Additionally, the glass transition temperature (Tg) and integral procedural decomposition temperature of epoxy composites with oxyfluorinated EG show the increase of 6% (4.4 °C) and 106% (264 °C), respectively, which indicated the improvement in thermal stability. These results can be attributed to the interfacial interaction between epoxy and oxyfluorinated EG, which formed strong interfacial interactions between the epoxy resin and EG due to the presence of oxygen- and fluorine-containing functional groups in oxyfluorinated EG.

Preparation and Characteristics of an Environmentally Friendly Hyperbranched Flame-Retardant Polyurethane Hybrid Containing Nitrogen, Phosphorus, and Silicon.

The NCO functional group of 3-isocyanatoproplytriethoxysilane (IPTS) and the OH functional group of 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phospha-phenantbrene-10-oxide (DOPO-BQ) were used to conduct an addition reaction. Following completion of the reaction, triglycidyl isocyanurate (TGIC) was introduced to conduct a ring-opening reaction. Subsequently, a sol–gel method was used to initiate a hydrolysis–condensation reaction on TGIC–IPTS–DOPO-BQ to form a hyperbranched nitrogen–phosphorous–silicon (HBNPSi) flame retardant. This flame retardant was incorporated into a polyurethane (PU) matrix to prepare a hybrid material. Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), limiting oxygen index (LOI), UV-VIS spectrophotometry, and Raman analysis were conducted to characterize the structure and analyze the transparency, thermal stability, flame retardancy, and residual char to understand the flame retardant mechanism of the prepared hybrid material. After the flame retardant was added, the maximum degradation rate decreased from −36 to −17 wt.%/min, the integral procedural decomposition temperature (IPDT) increased from 348 to 488 °C, and the char yield increased from 0.7 to 8.1 wt.%. The aforementioned results verified that the thermal stability of PU can be improved after adding HBNPSi. The LOI analysis indicated that the pristine PU was flammable because the LOI of pristine PU was only 19. When the content of added HBNPSi was 40%, the LOI value was 26; thus the PU hybrid became nonflammable.

Improving Thermal Stability of Polyurethane through the Addition of Hyperbranched Polysiloxane.

Polydimethylsiloxane with hydroxy groups was functionalized to form functionalized polydimethylsiloxane, which subsequently underwent an addition reaction with isophorone diisocyanate to form the prepolymer. Next, 3-aminopropyltriethoxysilane (APTS) reacted with 3-glycidoxypropyltrimethoxysilane (GPTS) to produce bridged polysilsesquioxanes, and sol-gel technology was employed to form hyperbranched polysiloxane nanoparticles with hydroxy groups, APTS-GPTS, which was used as the additive. The hyperbranched polysiloxane and the prepolymer containing NCO functional groups then underwent an addition reaction to produce the hybrid materials. Fourier-transform infrared spectroscopy and 29Si nuclear magnetic resonance were used to characterize the structure of the polyurethane hybrid. Regarding thermal stability, after the hyperbranched polysiloxane nanoparticles was introduced, the integral procedural decomposition temperature increased from 348 °C for polyurethane matrix to 859 °C for the hybrid material. The results reveal that the thermal stability of the hybrid material substantially increased by approximately 247%.

Development of coordination polyureas derived from amine terminated polyurea and metal ions having 'd5', 'd7', 'd8' and 'd10' orbitals: From synthesis to applications.

Amine terminated polyureas [ATPUa] were synthesized by 'in situ' condensation polymerization of toluene diisocyanate (TDI) with equimolar ratio of ethylene diamine (ED) and water. Incorporating the completely half-filled {Mn(II) d5}, partially filled {Co(II) d7, Ni(II) d8} and fulfilled {Zn(II) d10} divalent metal ions in APTUa generated the coordination polyureas (CPa). The structure and geometry of resulting CPa was ascertained by spectral techniques, the Fourier transform (FTIR), UV-Visible and nuclear magnetic resonance (1H NMR) spectroscopy. Amorphous/semi-crystalline and rough/layered surface morphology was analyzed by X-ray diffraction analysis (XRD) and field emission scanning electron microscopy along with energy dispersive X-ray spectroscopy (FESEM/EDX). Good thermal stability was observed having the trend, ATPUa-Zn(II) > ATPUa-Mn(II) > ATPUa-Co(II) > ATPUa-Ni(II) > ATPUa [with IPDT values, 712 °C of ATPUa-Zn(II), 673 °C of ATPUa-Mn(II), 582 °C of ATPUa-Co(II), 563 °C of ATPUa-Ni(II), 488 °C of ATPUa] respectively. It was analyzed by thermo-gravimetric, differential thermal, differential scanning calorimetry and integral procedure decomposition temperature analysis (TGA/DTA/DSC/IPDT). Good adsorption/desorption behavior of CPa was analyzed with the help of batch adsorption techniques, and it was found that CPa {in order; ATPUa-Ni(II) > ATPUa-Mn(II)}can be used as effective dye adsorbent (up to 97%) for the waste water treatment. The CPa were screened for their in-vitro antimicrobial activity against six gram positive and three gram negative bacterial strains as compared to standard drug (Ciprofloxacin and Gentamicin) and moderate antimicrobial activity was observed.

Synthesis and Characterization of Polystyrene (PS)/Modified Ni‐Al LDH Nanocomposite: Role of Composition, Modifier and Synthesis Route of Layered Double Hydroxides (LDH)

Layered double hydroxides (LDH) are two‐dimensional nanostructured materials, which impart flame retardancy property and improvement in various properties on incorporation into the polymer matrix. In this study, Ni‐Al LDH with a molar ratio of 2:1 and 3:1 (2NiAl and 3NiAl) was prepared by co‐precipitation method and Ni‐Al LDH with a molar ratio of 2:1 (NiAl urea) was also synthesized by the urea hydrolysis method. As the d‐spacing of these as‐synthesized LDHs is very small (≈0.8 nm) as well as hydrophilic in nature, hence, the unmodified LDHs are unsuitable for polymer nanocomposite preparation. In order to enhance the d‐spacing of LDHs, a simple regeneration method was employed to organically modify LDHs using two anionic surfactants such as sodium dodecyl benzene sulfate (SDBS) and sodium dodecyl sulfate (SDS). The hydrophobic tail of these anionic surfactants replaced the nitrate ions present in the unmodified LDHs leading to higher d‐spacing value, which was evident from XRD analysis. The above prepared LDHs (3 wt%) were incorporated into PS matrix by the solvent blending method to make PS nanocomposites. The 003 peak of modified LDHs did not appear in the XRD pattern of PS nanocomposites due to the disorientation of LDH layers in the PS matrix that was confirmed by TEM analysis. The TGA results clearly demonstrated that the thermal stability of the PS nanocomposite samples was increased by 26, 22 and 22 °C (PS/2NiAl SDS, PS/3NiAl SDS, and PS/NiAl urea SDS) for SDS modified LDH fillers, while in the case of SDBS modified LDH fillers, the improvement was around 32 °C in comparison with PS, when 15% weight loss was taken as a reference. The degradation mechanism, thermal degradation kinetics, and integral procedural decomposition temperature (IPDT) for all the nanocomposite systems were also evaluated using Criado method, Coats‐Redfern method, and Doyle's method, respectively. The effect of dispersion of the modified LDH fillers into PS matrix was examined using melt rheological analysis.

Diglycidyl ether of bisphenol A/chitosan‐graft‐polyaniline composites with electromagnetic interference shielding properties: Synthesis, characterization, and curing kinetics

Conducting filler based on chitosan and grafted polyaniline (Ch‐g‐PANI) was prepared with different grafting ratios and used as fillers for polyester powder coating system. Differential scanning calorimetry is applied to study the effect of Ch‐g‐PANI on the curing of the polyester powder coating. The activation energy calculated by isoconversional Kissinger method was increased by either increasing the Ch‐g‐PANI content or the content of polyaniline in the filler, suggesting the contribution of the filler in the curing reactions. The cured samples were characterized using FTIR and TG analyses. Thermogravimetric analysis showed that the total thermal stability was enhanced upon the filler addition as detected from the values of integral procedural decomposition temperature. Furthermore, a dielectric study showed that the dielectric constant and loss were increased upon increasing of the filler. Vogel–Fulcher–Tammann equation was well‐fitted when used to examine the dependence of α‐relaxation on the temperature and the dielectrically calculated Tg values were comparable to that measured by DSC. The shielding effectiveness toward microwaves was enhanced by increasing the filler content. POLYM. ENG. SCI., 59:372–381, 2019. © 2018 Society of Plastics Engineers

Study on thermal and mechanical properties of cellulose/iron oxide bionanocomposites film

Abstract The cellulose/iron oxide films were synthesized by a simple solution mixing-curing method. The structural elucidation of these films was made, using Fourier transform infrared spectroscopy (FTIR) and X-ray diffractions (XRD). The homogeneous dispersion of iron oxide in nanocomposites and morphology of their films were analyzed by Scanning Electron Microscopy (SEM). Thermal stability was conducted with the help of Thermogravimetric Analyzer (TGA). The improved Integral Procedural Decomposition Temperature (IPDT) value confirms that cellulose/iron oxide is more thermally stable than cellulose film . The tensile stress test was conducted to analyze the mechanical properties of cellulose, cellulose/(0.5 wt%)Fe 3O4, cellulose/(1 wt%)Fe3O4 and cellulose/(2 wt%)Fe3O4 nanocomposites films . The tensile strength and Young modulus of the cellulose/(1 wt%)Fe 3O4 nanocomposites films were observed as 9.42 ± 0.6% and 45.16 ± 0.4% higher than that of the cellulose film, respectively. The physico-mechanical properties of these films suggest that the iron oxide based cellulose nanocomposite films may have a potential scope for their application in packaging industries.

Novel biodegradable and antibacterial edible films based on alginate and chitosan biguanidine hydrochloride

Novel bioactive edible films based on sodium alginate (A) and chitosan biguanidine hydrochloride (CG) with different weight percents were successfully prepared. 13C NMR and 1H NMR confirmed the successful guanidylation of chitosan. Fourier transform infrared confirmed the successful reaction between CG and A. The interaction between CG and A was confirmed through the reduction of the crystalline peaks of both CG and A as detected from their wide-angle X-ray diffraction. Thermogravimetric analysis confirmed that CG enhanced the thermal stability of films as detected from the calculated integral procedure decomposition temperature (IPDT) values. CG incorporation improved the mechanical properties of dry and wet samples. A/CG films exhibited a reduced water vapor permeability and good color properties. The antibacterial study proved that the prepared films showed a remarkable antibacterial killing ability. These results revealed that A/CG films could be an alternative candidate to be used as antibacterial edible films in food industries.

The thermal decomposition behavior and kinetics of epoxy resins cured with a novel phthalide-containing aromatic diamine

The thermal decomposition behaviors and kinetics of diglycidyl ether of bisphenol A (DGEBA) epoxy resin cured by a novel phthalide-containing aromatic diamine (BAPP), were studied by thermal gravimetric analysis (TGA) technique in comparison with these of epoxy systems cured by 4,4′-diaminodiphenylsulfone (DDS) and equimolar mixture of DDS/BAPP, respectively. The initial decomposition temperature (Tinitial) and integral procedure decomposition temperature (IPDT) were used to evaluate the thermal stability of cured epoxy resins. Tinitial values are reduced with increasing BAPP content, while IPDT results show the cured DGEBA/BAPP system has the highest inherent thermal stability. The microstructure morphology of charred products, derived from the thermal decomposition of the cured epoxy networks, were characterized by scanning electron microscope (SEM). The decomposition kinetics was investigated by isoconversional approach and the activation energy (Ea) calculated by Starink equation exhibits different dependence on conversion (α) for three epoxy systems. Truncated Sestak-Berggren model was used to describe the thermal decomposition mechanism, and the result shows a good agreement between the experimental data and the theoretical model.

Alumina-graphene hybrid filled epoxy composite: Quantitative validation and enhanced thermal conductivity

Abstract Alumina-graphene hybrid fillers (Gr-Al2O3) were synthesized and added to the epoxy matrix to improve thermal properties of the epoxy composite. The alumina particles were surface modified with silane coupling agents like 3-Aminopropyl triethoxysilane (A-Al2O3). 3-Glycidyloxypropyl trimethoxysilane (GPTMS) was used for the surface modification of the graphene (G-Graphene). These modifications on the filler surface help to develop the interface between the fillers and the epoxy matrix, which might help to form the effective 3D thermal conductive networks. The generation of these 3D networks facilitated in reducing the Kapitza resistance and increases the transportation of phonons in the matrix, Furthermore; it improved the integral procedure decomposition temperature (IPDT) and activation energy (Ea) of the composite. Alumina-graphene hybrid filled epoxy composite (hAG-Epoxy) with 50 vol% of hybrid filler (Gr-Al2O3) expressed the considerable improvement in in-plane thermal conductivity and IPDT by ∼8.4 and ∼3.1 folds in comparison with neat epoxy, respectively. The significant improvement in thermal conductivity was related to the generation of effective 3D thermal conductive pathways formed by 2D graphene and 1D alumina in the composite.

Synthesis, vibrational spectrometry and thermal characterizations of coordination polymers derived from divalent metal ions and hydroxyl terminated polyurethane as ligand

A series of novel coordination polyurethanes [HTPU-M, where M=Mn(II) ‘d5’, Ni(II) ‘d8’, and Zn(II) ‘d10’] have been synthesized to investigate the effect of divalent metal ions coordination on structure, thermal and adsorption properties of low molecular weight hydroxyl terminated polyurethane (HTPU). HTPU-M have been synthesized in situ where, OH group of HTPU (synthesized by the condensation polymerization reaction of ethylene glycol (EG) and toluene diisocyanate (TDI) in presence of catalyst) on condensation polymerization with metal acetate in presence of acid catalyst synthesized HTPU-M followed by coordination of metal ions with hetero atoms. The structure, composition and geometry of HTPU-M have been confirmed by vibrational spectrometry (FTIR), 1H NMR, elemental analysis and UV–Visible spectroscopy. Morphological structures of HTPU-M were analyzed by X-Ray Diffraction analysis (XRD), Field Emission Scanning Electron Microscope (FE-SEM) with Energy Dispersive X-ray spectroscopy (EDX) and High Resolution Transmission Electron Microscope (HR-TEM) techniques. The thermal degradation pattern and thermal stability of HTPU-M in comparison to HTPU was investigated by thermal-gravimetric (TG)/differential thermal (DT), analyses along with Integral procedure decomposition temperature (IPDT) by Doyle method. The molecular weight of HTPU was determined by gel permeation chromatography (GPC). The preliminary adsorption/desorption studies of HTPU-M for Congo red (CR) was studied by batch adsorption techniques.The results indicated that HTPU-M have amorphous, layered morphology with higher number of nano-sized grooves in comparison to HTPU. Coordination of metal to HTPU plays a key role in enhancing the thermal stability [HTPU-Ni(II)>HTPU-Mn(II)>HTPU-Zn(II)>HTPU]. The HTPU-M can be utilized for industrial waste water treatment by removing environmental pollutants.

Nanodiamond nanocluster-decorated graphene oxide/epoxy nanocomposites with enhanced mechanical behavior and thermal stability

Novel hybrid fillers composed of nanodiamond (ND) nanocluster-decorated graphene oxide (GO) were fabricated and incorporated in an epoxy matrix using a facile thermoregulatory liquid-liquid extraction method. X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses confirmed a chemical bonding between the (3-aminopropyl)triethoxysilane-functionalized ND and (3-glycidyloxypropyl)trimethoxysilane-functionalized GO. The morphology of the hybrid filler (GN) was characterized by field-emission transmission electron microscopy. ND nanoclusters with an average diameter of 50–100 nm were uniformly grown on the GO surface. The hybrid filler provided significant enhancement of mechanical properties, such as flexural strength, flexural modulus, and fracture toughness. In particular, the epoxy composite containing 0.1 wt% of GN hybrid exhibited a stronger mechanical behavior compared to that containing 0.2 wt% of GO. As the GN loading increased, the thermal stability, the integral procedural decomposition temperature, and the activation energy increased as well. The toughening mechanism was illustrated by a microcrack theory based on the microscopic analysis of the fracture surfaces. The presence of ND nanoclusters not only hindered the aggregation of the GO sheets, but also played a crack pinning role in the polymer-matrix composites, which could significantly enhance its fracture toughness.

전기방사법에 의해 제조된 폴리우레탄 나노섬유의 수산화알루미늄 내첨에 의한 내염화 특성 향상

본 논문에서는 내산화성 및 난연성이 향상된 폴리우레탄 나노섬유를 전기방사법 및 수산화알루미늄 내첨을 통해 제조하였다. 전기방사 조건은 인가전압: 20 kV, 폴리머 용액 유량: 1.2 ml/h, 롤러 속도: 120 rpm 및 롤러와 주사기 팁의 거리: 15 cm의 공정변수에서 최적의 조건을 확인하였다. 폴리우레탄 섬유의 내산화성 및 난연성을 향상시키기 위하여, 수산화알루미늄을 전기방사 시 내첨하였다. 제조된 샘플의 열적 특성을 평가하기 위하여 열중량분석기(thermogravimetric analysis, Shimadzu, TGA-50H)를 사용하였다. 또한 관련 분석을 통해 고분자 분해 온도(polymer decomposition temperature), 적분열분해 진행온도(integral procedure decomposition temperature), 최종 분해 온도(final decomposition temperature) 및 열분해 후 잔여량 등을 분석하였다. 그리고 분해 반응의 속도론적 고찰을 위해 Horowitz-Metzger 적분식을 통해 활성화 에너지를 해석하였다. 수산화알루미늄의 내첨에 의해, 분해 활성화 에너지가 50% 이상 증가함을 확인하였다. 이는 수산화알루미늄이 <TEX>$300{\sim}500^{\circ}C$</TEX>에서 열분해함에 따라 수화반응에 의해 폴리우레탄 나노섬유의 열분해 저항성이 커지기 때문인 것으로 파악된다. Anti-oxidation and flame resistant polyurethane nanofibers were prepared by electrospinning and aluminum hydroxide addition. Electrospinning was carried out under the following procedure conditions; applied voltage, 20 kV; polymer solution feeding rate, 1.2 ml/h; collector rolling speed, 120 rpm; and tip to collector distance, 15 cm. Aluminum hydroxide was added to the prepared polymer solution for electrospinning to enhance the oxidation and flame resistant properties. The thermal properties were investigated by thermogravimetric analysis to determine the polymer decomposition temperature, integral procedure decomposition temperature, final decomposition temperature, and remaining amount after thermal decomposition. The activated energy for polymer degradation was also investigated using the Horowitz-Metzger equation. The activation energy increased to more than 50%. The thermal properties of the polyurethane nanofibers were improved by a hydration reaction during the thermal decomposition of aluminum hydroxide around <TEX>$300{\sim}500^{\circ}C$</TEX>.

Morphology, thermal stability and thermal degradation kinetics of cellulose-modified urea–formaldehyde resin

This article reports a study on the structural characterization and evaluation of thermal degradation kinetics of urea–formaldehyde resin modified with cellulose, known as UFC resin. Structural characterization of UFC undertaken by scanning electron microscopy, Fourier transform infrared and X-ray diffraction analyses reveals that the resin is fairly homogenous, and it constitutes of partly crystalline structure including urea–formaldehyde/cellulose interface morphology different from UFC precursors. Measurement of inherent thermal stability, probing reaction complexity and the thermal degradation kinetic analysis of UFC have been carried out by thermogravimetric/differential thermal analyses (TGA/DTA) under non-isothermal conditions. The integral procedure decomposition temperature elucidates significant thermal stability of UFC. TGA/DTA analyses suggest highly complicated reaction profile for thermal degradation of UFC, comprising various parallel/consecutive reactions. Different differential and integral isoconversional methods have been employed to determine the thermal degradation activation energy of UFC. Substantial variation in activation energy with the advancement of reaction verifies multi-step reaction pathway of UFC. A plausible interpretation of the obtained kinetic parameters of UFC thermal degradation with regard to their physical meanings is given and discussed in this study.

A simple solvent blending coupled sonication technique for synthesis of polystyrene (PS)/multi-walled carbon nanotube (MWCNT) nanocomposites: Effect of modified MWCNT content

Abstract The influence of carboxylic acid functionalized multi-walled carbon nanotubes (cMWCNTs) content on the properties of polystyrene (PS) nanocomposite (NC) films was investigated. The NC films were produced by a simple sonication assisted solvent blending technique. The interaction between the matrix (PS) and well dispersed filler (cMWCNT) was evaluated by different techniques involving Fourier transform infrared spectroscopy, Raman spectroscopy and X-Ray diffraction. Morphological images of the NCs were collected from Transmission electron microscopy. The thermal characteristics of the PS were found to be improved by the incorporation of the cMWCNTs, which was evident from the Thermogravimetric analysis (TGA) data. The thermal degradation activation energy evaluated by Coats-Redfern method and integral procedural decomposition temperature determined by Doyle's method supported the thermal stability proposed by TGA of the NCs. The reaction mechanism of thermal degradation of neat PS and respective NCs was successfully predicted using Criado method. The rheological properties and hardness were found to be upgraded by the inclusion of nanotubes to the PS matrix.

Thermal, impact and toughness behaviors of expanded graphite/graphite oxide-filled epoxy composites

Abstract Expanded graphite (EG)/graphite oxide (GO)-filled composites were prepared and their thermal and mechanical properties were investigated. The thermal behaviors of the composites were examined by performing differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA) measurements. The mechanical properties were determined by measuring the impact strength and calculating the critical stress intensity factor ( K IC ). The results obtained in this study indicated that the thermal stability value, which was calculated using the integral procedural decomposition temperature (IPDT), increased from 391.0 °C to 406.0 °C. The fracture toughness of the composites is improved by approximately 64% with the addition of co-carbon fillers. Notably, the co-carbon fillers contributed to improved interfacial interaction between the epoxy resin and the fillers.

Solid state thermal degradation behaviour of graft copolymers of carboxymethyl cellulose with vinyl monomers

The graft copolymer of sodium carboxymethyl cellulose (CMC) with acrylamide (ACM), dimethylacrylamide (DMA), N-vinyl pyrrolidone (NVP), 2-acrylamido-2-methyl-1-propane sulphonic acid (AMPS) and vinyl caprolactum (VCL) were synthesized in nitrogen atmosphere by employing redox initiators. The integral procedural decomposition temperature (IPDT) of CMC and its graft copolymer with ACM, DMA, AMPS, NVP and VCL have been found to be 274°C, 375°C, 421°C, 404°C, 466°C and 331°C, respectively. The higher value of IPDT showed more thermal stability. Among all five graft copolymers, the graft copolymer of CMC with NVP is thermally more stable and VCL grafted copolymer was found least thermally stable. The higher char yield and final decomposition temperature (FDT) were obtained in the case of more thermally stable graft copolymer. All five graft copolymers have shown more than one Tmax, which suggests that degradations were multistep process.

Synergistic effects of 4A zeolite on the flame‐retardant properties and thermal stability of an efficient halogen‐free flame‐retardant EVA composite

The synergistic effects of 4A zeolite (4A) on the thermal degradation, flame retardancy, and char formation of an efficient halogen‐free flame‐retardant ethylene‐vinyl acetate copolymer composite (EVA/IFR) were investigated by limited oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test (CCT), digital photography, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), laser Raman spectroscopy (LRS) and thermogravimetric analytical (TGA) methods. It was found that a small amount of 4A clearly improved the LOI value of the EVA/IFR composite and reinforced the fire retardant performance with a great reduction in the combustion parameters of the EVA/IFR system from the CCT test. The entire composites passed the UL‐94 V‐0 rating test. The TGA and integral procedure decomposition temperature (IDPT) results showed that 4A enhanced the thermal stability of the EVA/IFR system and increased the char residue content effectively. The morphological structures observed by digital and SEM imaging revealed that 4A could promote EVA/IFR to form a more continuous and compact intumescent char layer. The LRS and EDS results demonstrated that by introduction of 4A into the EVA/IFR system, a more graphite structure was formed with increase phosphorus content in the char residue. POLYM. ENG. SCI., 56:380–387, 2016. © 2016 Society of Plastics Engineers