scholarly journals A Characteristic Study of Polylactic Acid/Organic Modified Montmorillonite (PLA/OMMT) Nanocomposite Materials after Hydrolyzing

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 376
Author(s):  
Su-Mei Huang ◽  
Jiunn-Jer Hwang ◽  
Hsin-Jiant Liu ◽  
An-Miao Zheng
Keyword(s):  
Thermal Stability ◽  
Polylactic Acid ◽  
Decomposition Temperature ◽  
Material Strength ◽  
Scanning Calorimetry ◽  
Hydrolysis Process ◽  
Twin Screw ◽  
Thermal Pressing ◽  
Organophilic Clay ◽  
Mmt Clay

In this study, the montmorillonite (MMT) clay was modified with NH4Cl, and then the structures were exfoliated or intercalated in a polylactic acid (PLA) matrix by a torque rheometer in the ratio of 0.5, 3.0, 5.0 and 8.0 wt%. X-ray diffraction (XRD) revealed that the organic modified-MMT(OMMT) was distributed successfully in the PLA matrix. After thermal pressing, the thermal stability of the mixed composites was measured by a TGA. The mixed composites were also blended with OMMT by a co-rotating twin screw extruder palletizing system, and then injected for the ASTM-D638 standard specimen by an injection machine for measuring the material strength by MTS. The experimental results showed that the mixture of organophilic clay and PLA would enhance the thermal stability. In the PLA mixed with 3 wt% OMMT nanocomposite, the TGA maximum decomposition temperature (Tmax) rose from 336.84 °C to 339.08 °C. In the PLA mixed with 5 wt% OMMT nanocomposite, the loss of temperature rose from 325.14 °C to 326.48 °C. In addition, the elongation rate increased from 4.46% to 10.19% with the maximum loading of 58 MPa. After the vibrating hydrolysis process, the PLA/OMMT nanocomposite was degraded through the measurement of differential scanning calorimetry (DSC) and its Tg, Tc, and Tm1 declined.

Thermal behavior of modified poly(L-lactic acid): effect of aromatic multiamide derivative based on 1H-benzotriazole

e-Polymers ◽  
2016 ◽  
Vol 16 (4) ◽  
pp. 303-311 ◽  
Author(s):  
Yan-Hua Cai ◽  
Li-Sha Zhao
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Onset Crystallization Temperature

AbstractThe goal of this work was to synthesis a novel aromatic multiamide derivative based on 1H-benzotriazole (PB) as an organic nucleating agent for poly(L-lactic acid) (PLLA), and investigate the effect of PB on the non-isothermal crystallization, melting behavior and thermal decomposition of PLLA. Here, PB was firstly synthesized through 1H-benzotriazole aceto-hydrazide and terephthaloyl chloride, then PB-nucleated PLLA was fabricated via melt-blending technology at various PB concentration from 0.5 wt% to 3 wt%. Finally, the thermal performances were evaluated through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The high thermal decomposition temperature of PB indicated that PB possessed possibility as a nucleating agent for PLLA, and the non-isothermal crystallization behavior confirmed the crystallization accelerating effectiveness of PB for PLLA. Upon optimum concentration of 2 wt%, the onset crystallization temperature, the crystallization peak temperature and the non-isothermal crystallization enthalpy increased from 101.4°C, 94.5°C and 0.1 J·g-1 to 121.3°C, 115.8°C and 35.1 J·g-1, respectively. In addition, the non-isothermal crystallization behavior was also affected by the cooling rate and the final melting temperature. The melting behavior further evidenced the advanced nucleating ability of PB, and the competitive relationship between PB and the heating rate, the nuclear rate and crystal growth rate. Thermal stability measurement showed that PB with a concentration of 1 wt%–2 wt% could slightly improve the thermal stability of PLLA.

Synthesis of Flame-retardant Phosphaphenanthrene Derivatives with High Phosphorus Contents

2014 ◽  
Vol 67 (11) ◽  
pp. 1688 ◽  
Author(s):  
Jinyun Zheng ◽  
Yujian Yu ◽  
Lulu Zhang ◽  
Xiaomin Zhen ◽  
Yufen Zhao
Keyword(s):  
Thermal Stability ◽  
Flame Retardant ◽  
High Resolution Mass Spectrometry ◽  
Lithium Ion ◽  
Decomposition Temperature ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
High Phosphorus ◽  
Phosphorylation Reaction ◽  
Flame Retardant Properties

Two novel types of phosphate derivatives of phosphaphenanthrene with a high phosphorus content were prepared by phosphorylation reaction between either 2-(6-oxido-6H-dibenz<c,e><1,2>oxaphosphorin-6-yl)-methanol (ODOPM) or 2-(6-oxido-6H-dibenz<c,e><1,2>oxaphosphorin-6-yl)-1,4-benzenediol (ODOPB) and dialkyl phosphoryl chloride. The structures of all compounds were characterised by 1H NMR, 13C NMR, 31P NMR, Fourier transform infrared spectroscopy, and high-resolution mass spectrometry. The thermal stability of representative compounds was determined by thermal gravimetric analysis and differential scanning calorimetry. The results showed that the compounds have excellent resistance to oxidation, high thermal stability with an onset decomposition temperature above 200°C, and a high char yield over 25 %, owing to the high P content. The representative compound was added to conventional electrolytes of lithium-ion batteries as flame retardant additive, and the self-extinguishing time and ionic conductivity were measured. The result showed that the compounds have effective flame retardant properties.

Effect of different amounts of modified talc on the mechanical, thermal, and crystallization properties of poly(butylene succinate)

2014 ◽  
Vol 34 (4) ◽  
pp. 379-385 ◽  
Author(s):  
Bingxin Sun ◽  
Chengzhi Chuai ◽  
Si Luo ◽  
Ying Guo ◽  
Chunyang Han
Keyword(s):  
Thermal Stability ◽  
Mechanical Test ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Electron Microscopic ◽  
Butylene Succinate ◽  
Crystallinity Degree ◽  
Crystallization Properties ◽  
Twin Screw ◽  
Microscopic Studies

Abstract Poly(butylene succinate) (PBS) with different ratios of modified talc was prepared by twin-screw extruding. The effect of different loading amounts of talc on the mechanical, thermal, and crystallization properties of PBS was investigated. The mechanical test results indicate that the stiffness of the composites was increased linearly with increasing talc content, and the tensile strength and elongation stayed at relatively high levels when the talc amount is <15 phr. Thermal gravimetric analysis showed that the thermal stability of PBS composites was improved notably with a small amount (5–10 phr) of talc; however, high loading of talc did not help further improve the thermal stability. Differential scanning calorimetry data showed that the melting enthalpy (ΔHm), crystallization enthalpy (ΔHc), and crystallinity degree (Xc) decreased when the talc increased and crystallization temperature (Tc) was moving to relatively high values. The results of X-ray diffraction demonstrated that the incorporation of talc inhibited the PBS crystallization behavior significantly but did not change the crystal structure. Scanning electron microscopic studies indicated that the homogeneous dispersion and smoother fracture surfaces of the composite became inhomogeneous and coarse with higher talc loading.

scholarly journals An Investigation on the Comprehensive Property Assessment and Future Directions of Single Bamboo Fiber Reinforced Polypropylene Composites Fabricated by a Non-Woven Paving and Advanced Molding Process

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2641 ◽  
Author(s):  
Tang ◽  
Wang ◽  
Wang ◽  
Cheng ◽  
Guo
Keyword(s):  
Thermal Stability ◽  
Impact Strength ◽  
Water Resistance ◽  
Decomposition Temperature ◽  
Modulus Of Rupture ◽  
Gravimetric Analysis ◽  
Molding Process ◽  
Scanning Calorimetry ◽  
Bamboo Fibers ◽  
Thermal Stability Of

The demand for eco-friendly renewable natural fibers has grown in recent years. In this study, a series of polypropylene-based composites reinforced with single bamboo fibers (SBFs), prepared by non-woven paving and a hot-pressing process, were investigated. The influence of the content of SBF on impact strength, flexural strength, and water resistance was analyzed. The properties of the composites were greatly affected by the SBF content. Impact strength increased as SBF content increased. The modulus of rupture and modulus of elasticity show an optimum value, with SBF contents of 40% and 50%, respectively. The surface morphology of the fractured surfaces of the composites was characterized by scanning electron microscopy. The composites showed poor interfacial compatibility. The water resistance indicates that the composites with higher SBF contents have higher values of water absorption and thickness swelling, due to the hydrophilicity of the bamboo fibers. The thermal properties of the composites were characterized by thermal gravimetric analysis and by differential scanning calorimetry. The thermal stability of the composites was gradually reduced, due to the poor thermal stability of SBFs. In the composites, the maximum decomposition temperature corresponding to SBF shows an increasing trend. However, the maximum decomposition temperature of polypropylene was not influenced by SBF content. The melting point of the polypropylene in the composites was lower relative to pure polypropylene, although it was not affected by increasing SBF content.

scholarly journals Thermal Stability Analysis of Lithium-Ion Battery Electrolytes Based on Lithium Bis(trifluoromethanesulfonyl)imide-Lithium Difluoro(oxalato)Borate Dual-Salt

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 707
Author(s):  
Ya-Ping Yang ◽  
An-Chi Huang ◽  
Yan Tang ◽  
Ye-Cheng Liu ◽  
Zhi-Hao Wu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Model Fitting ◽  
Lithium Ion ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Thermal Decomposition Process ◽  
Autocatalytic Model ◽  
Pyrolysis Kinetic ◽  
Thermal Stability Of ◽  
Better Than

Lithium-ion batteries with conventional LiPF6 carbonate electrolytes are prone to failure at high temperature. In this work, the thermal stability of a dual-salt electrolyte of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium difluoro(oxalato)borate (LiODFB) in carbonate solvents was analyzed by accelerated rate calorimetry (ARC) and differential scanning calorimetry (DSC). LiTFSI-LiODFB dual-salt carbonate electrolyte decomposed when the temperature exceeded 138.5 °C in the DSC test and decomposed at 271.0 °C in the ARC test. The former is the onset decomposition temperature of the solvents in the electrolyte, and the latter is the LiTFSI-LiODFB dual salts. Flynn-Wall-Ozawa, Starink, and autocatalytic models were applied to determine pyrolysis kinetic parameters. The average apparent activation energy of the dual-salt electrolyte was 53.25 kJ/mol. According to the various model fitting, the thermal decomposition process of the dual-salt electrolyte followed the autocatalytic model. The results showed that the LiTFSI-LiODFB dual-salt electrolyte is significantly better than the LiPF6 electrolyte in terms of thermal stability.

Research on the preparation of heat-resistant epoxy resin cured by o-carborane-based diamine

2017 ◽  
Vol 30 (9) ◽  
pp. 1094-1100 ◽  
Author(s):  
Zhao Juan ◽  
Qing Ning ◽  
Jiang Shaohua ◽  
Wu Suping
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Epoxy Resin ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Initial Decomposition Temperature ◽  
Excellent Thermal Stability ◽  
Thermal Oxidative Stability ◽  
Air Atmosphere

A novel carborane-containing epoxy resin was prepared via the curing reaction between epoxy resin (E51) and 1,2-bis(4-aminophthalimide)dimethyl-1,2-dicarba-closododecaborane (4-AP CBR). According to the nonisothermal differential scanning calorimetry method and the T-β extrapolation method, the curing temperatures of the 4-AP CBR/E51 system were theoretically determined. The cured carboranyl epoxy resin was analyzed by thermogravimetric analysis (TGA), which revealed that the resin had excellent thermal stability and thermal oxidative stability. The results of TGA indicated that the initial decomposition temperature of the resin was exceeding 400°C and the char yield at 800°C was around 60% both under nitrogen and in air atmosphere.

scholarly journals Non-isothermal Crystallization, Thermal Stability, and Mechanical Performance of Poly(L-lactic acid)/Barium Phenylphosphonate Systems

2017 ◽  
Vol 15 (1) ◽  
pp. 248-254 ◽  
Author(s):  
Yan-Hua Cai ◽  
Li-Sha Zhao
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Mechanical Performance ◽  
Nucleating Agent ◽  
Crystal Form ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Crystallization Peak

AbstractThe introduction of a nucleating agent in semi-crystalline polymers is a frequently utilized way to improve the crystallization performance, and the use of a nucleating agent has a very great effect on the performance of the polymer in other areas including thermal stability and mechanical properties. In this investigation, barium phenylphosphonate (BaP) was prepared as a crystallization accelerator for Poly(L-lactic acid) (PLLA), and the non-isothermal crystallization behavior, thermal stability, and mechanical properties of PLLA modified by BaP were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and electronic tensile testing. Non-isothermal crystallization analysis showed that the BaP could significantly accelerate the crystallization of PLLA, and the non-isothermal crystallization peak shifted to a higher temperature with increasing concentration of BaP, however, the corresponding crystallization peak became wider. XRD results after non-isothermal crystallization confirmed the non-isothermal crystallization DSC results. Additionally, the addition of BaP did not change the crystal form of PLLA. A comparative study on thermal stability indicated that BaP decreased the onset decomposition temperature of PLLA, resulting from the formation of more tiny and imperfect crystals. Whereas the influence of BaP on the thermal decomposition profile of PLLA was negligible. In terms of mechanical properties, the tensile strength and elastic modulus of PLLA/BaP increased compared to the virgin PLLA, unfortunately, the elongation at break decreased.

scholarly journals Nylon 66/nano CaCO3 composites

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Peipei Yuan ◽  
Jianshu Zhong ◽  
Xisheng Liu
Keyword(s):  
Calcium Carbonate ◽  
Crystallization Temperature ◽  
Polarized Light ◽  
Decomposition Temperature ◽  
Melt Blending ◽  
Screw Extruder ◽  
Scanning Calorimetry ◽  
Nylon 66 ◽  
Twin Screw ◽  
Half Height Width

The nylon 66/nano-CaCO3 composites were prepared by melt blending on a twin-screw extruder. Scanning electron microscopy (SEM), polarized light microscopy (PLM), thermal loss (TGA) and differential scanning calorimetry (DSC) The effects of nanometer calcium carbonate on the polycrystalline behavior and thermal properties of nylon 66/nano CaCO3 composites were investigated. The results show that the nanometer calcium carbonate particles are dispersed in the nylon 66 matrix and exist in the form of aggregates. The nanometer calcium carbonate has the effect of heterogeneous nucleation, which can reduce the size of the spherules. The decomposition temperature of the nylon 66 is 400 ℃, the addition of nano-CaCO3 to reduce the decomposition temperature. At the same time, DSC test showed that the β-crystalline form in the material reduced the melting temperature of the material. The addition of nano-CaCO3 in the nylon 66 matrix resulted in the decrease of the crystallization temperature and the increase of the half-height width of the endothermic peak. The lower the crystallization temperature, the wider the crystallization temperature range.

scholarly journals Thermal Stability and Dynamic Mechanical Properties of Poly(ε-caprolactone)/Chitosan Composite Membranes

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5538
Author(s):  
Yanbo Zhang ◽  
Yaqi Wu ◽  
Ming Yang ◽  
Gang Zhang ◽  
Haiyan Ju
Keyword(s):  
Thermal Stability ◽  
Tissue Engineering ◽  
Composite Membranes ◽  
Dynamic Mechanical Properties ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Engineering Applications ◽  
Thermal Stabilities ◽  
Blend Ratio ◽  
Dynamic Mechanical

Poly (ε-caprolactone) (PCL) and chitosan (CS) are widely used as biodegradable and biocompatible polymers with desirable properties for tissue engineering applications. Composite membranes (CS–PCL) with various blend ratios (CS:PCL, w/w) of 0:100, 5:95, 10:90, 15:85, 20:80, and 100:0 were successfully prepared by lyophilization. The thermal stabilities of the CS–PCL membranes were systematically characterized by thermogravimetric analysis (TG), dynamic thermogravimetry (DTG), and differential scanning calorimetry (DSC). It was shown that the blend ratio of PCL and CS had a significant effect on the thermal stability, hydrophilicity, and dynamic mechanical viscoelasticity of the CS–PCL membranes. All the samples in the experimental range exhibited high elasticity at low temperature and high viscosity at high temperatures by dynamic mechanical thermal analysis (DMTA). The performances of the CS–PCL membranes were at optimum levels when the blend ratio (w/w) was 10:90. The glass transition temperature of the CS–PCL membranes increased from 64.8 °C to 76.6 °C compared to that of the pure PCL, and the initial thermal decomposition temperature reached 86.7 °C. The crystallinity and porosity went up to 29.97% and 85.61%, respectively, while the tensile strength and elongation at the breakage were 20.036 MPa and 198.72%, respectively. Therefore, the 10:90 (w/w) blend ratio of CS/PCL is recommended to prepare CS–PCL membranes for tissue engineering applications.

Thermal properties and thermal stability of polypropylene composites filled with graphene nanoplatelets

2017 ◽  
Vol 31 (2) ◽  
pp. 246-264 ◽  
Author(s):  
JZ Liang ◽  
JZ Wang ◽  
Gary CP Tsui ◽  
CY Tang
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Weight Fraction ◽  
Decomposition Temperature ◽  
Graphene Nanoplatelets ◽  
Filler Concentration ◽  
Scanning Calorimetry ◽  
Lateral Dimension ◽  
Polypropylene Composites ◽  
Thermal Stability Of

The thermal properties and thermal stability of polypropylene (PP) composites separately filled with graphene nanoplatelets (GNPs) with three different sizes were measured using a differential scanning calorimetry and a thermal gravimetric analyser. The results showed that the values of the melting temperature of the composites were higher than that of the unfilled PP; the thermal stability increased with increasing the weight fraction and lateral dimension of GNPs in the case of low filler concentration, while the effect of the GNPs thickness on the thermal stability was insignificant; the onset decomposition temperature increased with increasing the GNPs lateral dimension, while the maximum thermal decomposition rate increased first and then decreased with increasing the GNPs weight fraction. The thermal stability improvement should be attributed to the sheet barrier function of the GNPs.

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