Integral Procedural Decomposition Temperature Research Articles

에폭시/나일론6 블랜드의 경화 동력학 및 열안정성에 관한 연구

Abstract In this work, effects of the blend composition composed of 0, 10, 20, 30 and 40 wt% of nylon 6 to epoxy (diglycidylether of bisphenol-A, DGEBA) resin were investigated in terms of cure kinetics and thermal stability by differential scanning calo-rimeter (DSC) and thermogravimetric analysis (TGA). As the content of the nylon 6 increased, the maximum exothermic tem-perature (T max ) and the value of cure activation energy (E a ) decreased. The maximum exothermic temperature of the blending samples decreased with increasing in nylon 6 content, resulting in the decrease in curing activation energy of them due to the rapid curing reaction with epoxy resin in this system. From TGA analysis results of the DGEBA/nylon 6, the thermal stability based on the thermal stability index (A * ⋅K * ) and integral procedure decomposition temperature (IPDT) increased with increase in the nylon 6 content. This was because of the combination of DGEBA and nylon 6 having good heat resist-ance, resulting in improving thermal stability of the DGEBA/nylon 6.

Improvement of the mechanical and thermal properties of polyethersulfone-modified epoxy composites

We evaluated the use of polyethersulfone (PES) as reinforcement material to increase the mechanical and thermal properties of triglycidyl-p-aminophenol (TGAP) epoxy resin. The enhancement of the mechanical properties of the PES/epoxy composites was indicated by 44%, 35%, and 11% increases in tensile strength, impact strength, and fracture toughness, respectively. TGA revealed that the thermal stability of the PES/epoxy composites also improved by 17%, which was calculated using the integral procedural decomposition temperature (IPDT). These results are attributed to the good distribution and formation of the semi-interpenetrating polymer networks (semi-IPNs) that composed the epoxy network and the linear PES.

Study of thermal stability and thermo-mechanical behavior of functionalized soybean oil modified toughened epoxy/organo clay nanocomposite

Abstract In the current study, nano-clay was incorporated in toughened epoxy modified with epoxidized soybean oil (ESO) to improve the mechanical and thermal properties. Curing behavior was studied by Fourier Transform Infrared spectroscopy and Differential Scanning Calorimetry analysis to investigate the effect of ESO bioresin and nanoclay on cross-linking reaction. The increase in enthalpy of curing reaction and decrease in peak temperature of nanocomposite corroborated the catalytic effect of clay on the curing process. The thermal stability parameters like integral procedural decomposition temperature and decomposed activation energy were determined using Horowitz and Metzger equation. Dynamic mechanical analysis demonstrated the high storage modulus, improved crosslink density and good damping behavior of nanocomposite. Thermo mechanical analyzer was used to examine the coefficient of thermal expansion (CTE) of bio-based epoxy blend and nanocomposite in both glassy and rubbery region. The CTE value is decreased after addition of clay to the modified epoxy blend which confirmed the improved dimensional stability of the nanocomposite. TEM and X-ray diffraction analysis confirmed both intercalated and exfoliated clay platelet within the epoxy blend.

라이오셀의 열 안정 및 내산화 특성 향상을 위한 Na<sub>3</sub>PO<sub>4</sub> 내염화 처리

The improved thermal stability and anti-oxidation properties of lyocell fiber were studied based on flame retardant treatment by using Na PO solution. The optimized conditions of flame retardant treatment were studied on various concentrations of Na PO and the mechanism was proposed through experimental results of thermal stability and anti-oxidation. The integral procedural decomposition temperature (IPDT), limiting oxygen index (LOI) and activation energy (E ) increased 30, 160% respectively via flame retardant treatment. It is noted that thermal stability and anti-oxidation improved based on char and carbon layer formation by dehydrogenation and dissociation of C-C bond resulting the hindrance of oxygen and heat energy into polymer resin. The optimized conditions for efficient flame retardant property of lyocell fiber were provided using Na PO solution and the mechanism was also studied based on experimental results such as initial decomposition temperature (IDT), IPDT, LOI and E .

실란 커플링제에 따른 DGEBF 계열 에폭시의 열안정성 및 접착특성 평가

본 연구에서는 실란 커플링제의 함량에 따른 에폭시 복합재료의 열안정성 및 접착특성을 고찰하기 위하여, 일반적으로 널리 사용되는 diglycidyl ether of bisphenol F(DGEBF)계 에폭시수지에 실란 커플링제로는 3-glycidoxypropyl trimethoxysilane(GPTMS)를 변량 배합하여 에폭시 시편을 제조하였다. TGA 데이터를 통해 고분자 분해온도(polymer decomposition temperature, PDT), 최대 중량 감소 시의 온도(temperature of miximum rate of weight loss, <TEX>$T_{max}$</TEX>), 적분 열분해 진행 온도(integral procedural decomposition temperature, IPDT), 그리고 분해 활성화 에너지(<TEX>$E_a$</TEX>)를 구하였다. 또한 접착특성은 철판 사이에 제조한 에폭시 복합재료를 도포하여 접착력 시편을 제작하고, 상온에서 UTM(universal testing machine)을 사용하여 접착력을 측정하였다. 그 결과, DGEBF계 에폭시의 경우 실란커플링제 도입에 따라 미처리 에폭시 복합재료에 비해 접착력이 향상되었고, 일정 함량 도입 후에는 접착력이 오히려 감소하는 경향을 보였다. In this work, the epoxy specimens were prepared from diglycidyl ether of bisphenol F (DGEBF) with silane coupling agents (3-glycidoxypropyl trimethoxysilane (GPTMS)) in different ratios. Thermal stability was studied in terms of polymer decomposition temperature (PDT), temperature of maximum rate of weight loss (<TEX>$T_{max}$</TEX>), integral procedural decomposition temperature (IPDT), and decomposition activation energy (<TEX>$E_a$</TEX>) using TGA analysis. Adhesion properties of epoxy composite specimens were measured by UTM (universal testing machine) at atmosphere temperature. In this result, the adhesion properties of DGEBF were improved by addition of silane coupling agents compared to non-treated epoxy resin. However, when the content of GPTMS agent is more than 10 phr, adhesion properties decreased with increasing GPTMS agent.

Thermal stability and kinetics analysis of epoxy composites modified with reactive polyol diluent and multiwalled carbon nanotubes

ABSTRACTThe effect of polyether polyol and amino‐functionalized multiwalled carbon nanotubes (NH2‐MWCNTs) on the thermal stability of three‐phase (epoxy/polyol/NH2‐MWCNTs) epoxy composites was investigated. Thermal stability and degradation characteristics of polyol/MWCNTs modified epoxy composites was evaluated using thermogravimetric analysis. The kinetics of thermal degradation was assessed from data scanned at 5, 10, and 20°C/min. Activation energy for degradation of epoxy nanocomposites was calculated using different differential and integral methods, that is, Kissinger's, Flynn–Wall–Ozawa, Coats–Redfern, and Horowitz–Metzger methods. In addition, the integral procedure decomposition temperature was determined to evaluate the inherent thermal stability of the modified composite system. Rate of thermal degradation in MWCNT/Polyol samples was found to be reduced significantly while activation energy of degradation was increased compared to unmodified epoxy composite. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41558.

Novel high-loaded, nanoparticulate and thermally stable macromolecular prodrug design of NSAIDs based on hydroxypropylcellulose

Macromolecular prodrugs (MPDs) of aspirin and salicylic acid were synthesized by covalent attachment to hydroxypropylcellulose (HPC) using p-toluenesulfonyl chloride in N,N-dimethylacetamide. The present synthesis strategy resulted in organo-soluble MPDs with 78–86 % yield and degree of drug substitution 0.53–1.96 and 0.68–2.10 for aspirin and salicylic acid, respectively. The size exclusion chromatography showed DP 192 and 214 for HPC–aspirin and HPC–salicylic acid conjugates, respectively. HPC–aspirin and HPC–salicylic acid conjugates were found thermally more stable than native drugs. The activation energy (Ea) of thermal degradation of drugs, polymer and prodrugs was calculated with the help of Broido and Chang kinetic models. Order of reaction (n) was calculated from thermal data using Chang model. Various thermodynamic parameters, i.e., enthalpy (ΔH), Gibbs free energy (ΔG) and entropy (ΔS) were also calculated. Doyle’s method was employed on thermal data of MPDs to calculate integral procedural decomposition temperature and comprehensive index of intrinsic thermal stability. Amphiphilic HPC–aspirin conjugates showed formation of nanoparticles at water/DMSO interface with size distribution from ~500 to 750 nm by transmission electron microscopy.

Synthesis of a hyperbranched poly(phosphamide ester) oligomer and its high-effective flame retardancy and accelerated nucleation effect in polylactide composites

In this article, a hyperbranched poly(phosphamide ester) oligomer HBPE was prepared via A3 + BB′ method. FTIR spectrum, 1H and 31P NMR spectrum and GPC were utilized to characterize HBPE. Then HBPE was melt blended with PLA to fabricate flame retardant PLA composites. The integrated flame retardant property of PLA composites was investigated by LOI, UL-94, pyrolysis combustion flow calorimeter test (PCFC) and cone calorimeter test (CCT). The thermal stability of PLA composites was investigated by TGA, weight loss difference analysis and integral procedural decomposition temperature (IPDT). Results showed that PLA composite with only 2 wt% HBPE exhibited excellent flame retardancy (LOI = 33% and UL-94 V-0 rating) and 10 wt% HBPE imparted PLA composites largely increased LOI value of 43%. The incorporation of 10 wt% HBPE increased CO production rate (COP) and prolonged time to ignition (TTI) in CCT. Furthermore the thermal stability of PLA composites was enhanced from IPDT analysis. Meanwhile, DSC analysis of PLA composites showed Tg of PLA composites decreased slightly with the addition of HBPE, which indicated the limited plasticizing ability of HBPE in PLA composites. Finally, the accelerated nucleation effect was also detected in PLA composites using POM observation. Results showed HBPE was a high-effective flame retardant of PLA, exhibiting good nucleating property and limited plasticizing ability in PLA composites.

NaCl/H3PO4내염화 처리가 라이오셀 섬유의 열 안정 및 내산화 특성에 미치는 영향

The improved thermal stability and anti-oxidation properties of Lyocell fiber were studied based on flame retardant treatment by using NaCl/ solution. The optimized conditions of flame retardant treatment were studied on various maxing ratio of NaCl and and the mechanism was proposed through experimental results of thermal stability anti-oxidation. The IPDT (integral procedural decomposition temperature), LOI (limited oxygen index) and (activation energy) increased 23, 30 and 24% respectively via flame retardant treatment. It is noted that thermal stability and anti-oxidation improved based on char and carbon layer formation by dehydrogenation and dissociation of C-C bond resulting the hindrance of oxygen and heat energy into polymer resin. The optimized conditions for efficient flame retardant property of Lyocell fiber were provided using NaCl/ solution and the mechanism was also studied based on experimental results such as IDT (initial decomposition temperature), IPDT, LOI and .

Improved flame-retardant properties of lyocell fiber achieved by phosphorus compound

The anti-oxidation behavior of Lyocell fibers during flame-retardant treatment as a function of the effects of a phosphorus compound was explored. Di-ammonium-hydrogen phosphate (DAHP) was observed to reduce the thermal degradation rate of the Lyocell fibers and increase the char yield; DAHP also increased the limiting oxygen index via a first-order relationship with the char yield. The integral procedure decomposition temperature (IPDT) increased significantly, and the activation energy increased by a certain factor, indicating a slow degradation pathway involving dehydration, rearrangement, formation of carbonyl groups, evolution of carbon monoxide and carbon dioxide, and formation of a carbonaceous residue for the flame retardancy of Lyocell fibers.

Thermal Behavior of Epoxy Resins Containing Manganese Compounds

A novel cheap macromolecular intumescent flame retardants (Mn-MIFR), was synthesized. Epoxy resins (EP) were modified with Mn-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Mn contents of 4.0 % get a LOI of 26.5% and char yield of 18.2%. Dilatation, SDR and MSD of EP/Mn-MIFR decreased. The degradation behavior of the EP/Mn-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Mn and P at the residue were increased.

Combination effects of carbon nanotubes, MMT and phosphorus flame retardant on fire and thermal resistance of fiber-reinforced epoxy composites

The present work aims to enhance thermal stability and flame retardancy of the epoxy/glass composites containing carbon nanotubes (CNTs). To achieve this purpose ammonium polyphosphate (APP) as a micro filler and montmorillonite (MMT) as nanofiller have been used. Since good dispersion is necessary to achieve thermal and flame resistivity in nanocomposites, it was found that combination of ultrasonication and high shear flow can result in a good dispersion of nanoparticles in polymer matrix. Thus, all samples were prepared according to this method. In order to study thermal resistance and flame retardancy of the samples, thermal gravimetric analysis (TGA) and limiting oxygen index (LOI) have been employed, respectively. TGA results showed that combination of 0.5 wt% CNTs with either 5 wt% MMT or 15 wt% APP can increase the initial thermal decomposition temperature up to 62 °C for the former polymer composite and 47 °C for the latter one. Overall stabilization effect (OSE) and integral procedure decomposition temperature (IPDT) parameters have also been calculated from TGA data. These results showed that the sample containing a combination of APP and CNT has the highest value of OSE. Moreover, IPDT of this sample has increased about 9 % compared with the neat epoxy. LOI of the samples showed that the addition of MMT and CNTs together could increase LOI about 8 % and introduction of APP to these samples increased LOI about 10 %, as well.

Effect of natural and synthetic tackifiers on viscosities, adhesion properties and thermal stability of SNR and DPNR solution adhesives

Styrene-grafted natural rubber (SNR) and deproteinized natural rubber (DPNR) latexes were formulated with coumarone-indene (CI), gum rosin and petro resin (PR) tackifiers into solution adhesives with toluene as a solvent. The solution viscosities were evaluated by a Brookfield viscometer DV-II Plus with spindle No. 3. Pressure sensitive adhesives (PSAs) films were made and the adhesion properties were evaluated with loop tack, peel strength and shear strength tests. Thermal stability of the film was evaluated via Perkin-Elmer Pyris 6TM thermogravimetric analysis at temperatures ranging from 30 to 600 °C at a heating rate of 10 °C per minute in nitrogen environment. Results indicate that as the tackifiers content increased, the solution viscosities increased with SNR/PR and DPNR/PR formulations showing the highest viscosities. Adhesion test also indicates that loop tack and peel strength of the adhesive solution increased but their shear strength decreased; increase of CI tackifier loadings conferred the highest peel strength for both SNR- and DPNR-based PSAs. Thermal analyses show that the addition of 40 phr CI tackifiers improved thermal stability of SNR adhesives based on their higher Tmax and integral procedural decomposition temperature properties.

Effect of the particle size and solids volume fraction on the thermal degradation behaviour of Invar 36 feedstocks

Abstract Degradation kinetics and the thermal stability of Invar 36 powder injection moulding feedstocks (PIM) based on cellulose acetate butyrate (CAB) and polyethylene glycol (PEG) binders were investigated using simultaneous thermogravimetric analysis (STA) and differential scanning calorimetry (DSC). The initial decomposition temperature (IDT) and the integral procedure decomposition temperature (IPDT) were used to analyse the thermal stability of the binder system as a function of the solid loading content and powder particle size. The degradation kinetics was studied, and the process apparent activation energies were assessed using isoconversional methods. All the methodologies revealed changes in the thermal degradation behaviours of the feedstocks for solid loadings that were previously determined to correspond to optimal solid loadings using other experimental procedures. The studies also contrast previous similar findings with a ceramic powder. Therefore these results strengthen the proposal of thermodynamic degradation studies of feedstocks as an alternative or complementary technique to determine optimal solid loading contents in metal injection moulding (MIM).

Thermal analysis and gelation property of multifunctional epoxy resins used for pultruded composite ropes

Non-isothermal curing reactions of three different multifunctional epoxy resin systems were investigated by differential scanning calorimetry. The Kissinger equation was applied to calculate the apparent activation energy, and the Levenberg–Marquardt algorithm was used to fit the curing kinetic data. It was observed that the two-parameter model was in good match with the curing kinetics. In addition, dynamic mechanical thermal analysis was used to obtain the glass transition temperature (Tg). Furthermore, the thermal stabilities of the systems were studied by thermogravimetric (TG) analysis, the integral procedure decomposition temperature and temperature index Ts were used to characterize the thermal stability. Finally, the gelation time was measured by plate–knife method of a home-made device, and the relationship between gelation time and temperature was established, according to which the pultrusion process parameters were predicted.

Thermal Degradation of Epoxy Resins Containing Aluminum Compounds

A novel cheap macromolecular intumescent flame retardants (Al-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus-aluminum characterized by IR. Epoxy resins (EP) were modified with Al-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Al contents of 4.0 % get a LOI of 26.8% and char yield of 19.5%. Dilatation, SDR and MSD of EP/Al-MIFR decreased. The degradation behavior of the EP/Al-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Al and P at the residue were increased.

Thermal Degradation of Epoxy Resins Containing Copper Compounds

A novel cheap macromolecular intumescent flame retardants (Cu-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus-copper characterized by IR. Epoxy resins (EP) were modified with Cu-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Cu contents of 3.0 % get a LOI of 27.0% and char yield of 19.4%. Dilatation, SDR and MSD of EP/Cu-MIFR decreased. The degradation behavior of the EP/Cu-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Cu and P at the residue were increased.

Thermal stability and degradation kinetics of feedstocks for powder injection moulding – A new way to determine optimal solid loading?

Degradation kinetics and the thermal stability of zircon powder injection moulding feedstocks (PIM) based on cellulose acetate butyrate (CAB) and polyethylene glycol (PEG) binders were investigated using simultaneous thermogravimetric analysis (STA). The initial decomposition temperature (IDT) and the integral procedure decomposition temperature (IPDT) were used to analyse the thermal stability of the binder system as a function of the solid loading content. The degradation kinetics was studied, and the degradation activation energy was assessed for varying zircon powder contents using isoconversional methods. All the methodologies revealed changes in the thermal degradation behaviours of the feedstocks for solid loadings that were previously determined to correspond to optimal solid loadings using other experimental procedures. These results may promote the proposal of thermodynamic degradation studies of feedstocks as an alternative or complementary technique to determine optimal solid loading contents in powder injection moulding (PIM). The studies in this paper also examined PIM process operation temperatures for zircon feedstocks.

Preparation of a novel PEG composite with halogen-free flame retardant supporting matrix for thermal energy storage application

Poly (ethylene glycol) (PEG)/silsesquioxane composite was prepared by in situ sol–gel process. The structure of composite was characterized by solid state 31P and 29Si nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). N2 adsorption–desorption measurement was used to investigate the porous structure of supporting matrix. Thermal and flame retardancy properties were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and pyrolysis combustion flow calorimetry (PCFC). Results indicated the PEG composite showed large latent heat (124.7kJ/kg). After thermal cycling for 1000cycles, the composite still had large latent heat of 124.1kJ/kg, showing the composite had good thermal reliability property. The composite had obvious increased intrinsic thermal stability through analysis of integral procedural decomposition temperature (IPDT). The peak of heat release rate (PHRR) of composite was decreased by 38.6% compared with pure PEG. And the time to PHRR was increased by 31s compared with pure PEG. The novel shape-stabilized PEG composite had potential to become halogen-free fire resistance phase change composite for thermal energy storage application.

Epoxy Resins Treated with Magnesium-Containing Compounds in Material Engineering

A novel cheap macromolecular intumescent flame retardants (Mg-MIFR), was synthesized, and its structure was a caged bicyclic macromolecule containing phosphorus- magnesium characterized by IR. Epoxy resins (EP) were modified with Mg-MIFR to get the flame retardant EP, whose flammability and burning behavior were characterized by UL 94, limiting oxygen index (LOI), dilatation, char yield, smoke density rating (SDR) and maximum smoke density (MSD). The epoxy resins were obtained for the UL 94 V-0 rating at low Mg contents of 4.0% get a LOI of 27.0% and char yield of 19.8%. Dilatation, SDR and MSD of EP/Mg-MIFR decreased. The degradation behavior of the EP/Mg-MIFR was studied by TG and EDX analysis. The experimental results exhibited that the initial decomposition temperature (IDT) was decreased, integral procedure decomposition temperature (IPDT) and amounts of Mg and P at the residue were increased.