scholarly journals The preparation, physicochemical and thermal properties of the high moisture, solvent and chemical resistant starch-g-poly(geranyl methacrylate) copolymers

2019 ◽  
Vol 140 (1) ◽  
pp. 189-198 ◽  
Author(s):  
Marta Worzakowska
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Potato Starch ◽  
Hydroxyl Groups ◽  
Methacrylate Copolymers ◽  
Decomposition Processes ◽  
Methacrylate Monomer ◽  
A Minor ◽  
Subsequent Decomposition ◽  
Thermal Stability Of

Abstract The thermal properties together with the identification of the emitted volatiles during heating of the starch-graft-poly(geranyl methacrylate) copolymers with the use of a TG/FTIR-coupled method and some of the physicochemical properties of the copolymers were determined. It was found that the use of the geranyl methacrylate monomer to the graft copolymerization with potato starch allowed to replace ca. 1.46 hydroxyl groups per glycosidic units of starch macromolecule by the poly(geranyl methacrylate) chains under the optimal reaction conditions. Generally, all tested starch graft copolymers exhibited a significant increase in polar solvent resistance, moisture resistance and chemical stability as compared to potato starch. However, the thermal stability of the obtained materials was substantially lower as compared to the thermal stability of potato starch. The beginning of the decomposition of the copolymers was observed below 150 °C. It was due to low thermal stability of the poly(geranyl methacrylate) chains. The decomposition of the prepared materials runs at least four, unseparated stages. The first stage was visible up to 220–240 °C. It was connected with the emission of some aldehyde, acid, alcohol, alkene, ester fragments, H2O and CO2 as a result of the depolymerization, destruction and partial decarboxylation of the poly(geranyl methacrylate) chains. The second stage was spread between ca. 220–240 and 358–375 °C. The emission of organic, saturated, unsaturated, aromatic, oxygen-rich fragments, CO, CO2 and H2O as a result of the decomposition and dehydration of starch was confirmed. Heating of the studied materials between 358–375 and 455–477 °C resulted in subsequent decomposition processes of the residues and the creation of some oxygen-rich saturated and unsaturated fragments, CO, CO2, H2O and CH4. Finally, above 455–477 °C, a minor mass loss as a result of the decomposition processes of the residues formed before was observed. The emission of CO, CO2, H2O, CH4 and some oxygen-rich saturated and unsaturated fragments was confirmed.

scholarly journals Surface Modification of Cellulose Nanocrystals with Succinic Anhydride

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 866 ◽  
Author(s):  
Agnieszka Leszczyńska ◽  
Paulina Radzik ◽  
Ewa Szefer ◽  
Matej Mičušík ◽  
Mária Omastová ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Surface Modification ◽  
Thermal Properties ◽  
Reaction Time ◽  
Cellulose Nanocrystals ◽  
Succinic Anhydride ◽  
Molar Ratio ◽  
Hydroxyl Groups ◽  
Degree Of Esterification ◽  
Thermal Stability Of

The surface modification of cellulose nanocrystals (CNC) is a key intermediate step in the development of new functionalities and the tailoring of nanomaterial properties for specific applications. In the area of polymeric nanocomposites, apart from good interfacial adhesion, the high thermal stability of cellulose nanomaterial is vitally required for the stable processing and improvement of material properties. In this respect, the heterogeneous esterification of CNC with succinic anhydride was investigated in this work in order to obtain CNC with optimised surface and thermal properties. The influence of reaction parameters, such as time, temperature, and molar ratio of reagents, on the structure, morphology and thermal properties, were systematically studied over a wide range of values by DLS, FTIR, XPS, WAXD, SEM and TGA methods. It was found that the degree of surface substitution of CNC increased with the molar ratio of succinic anhydride to cellulose hydroxyl groups (SA:OH), as well as the reaction time, whilst the temperature of reaction showed a moderate effect on the degree of esterification in the range of 70–110 °C. The studies on the thermal stability of modified nanoparticles indicated that there is a critical extent of surface esterification below which only a slight decrease of the initial temperature of degradation was observed in pyrolytic and oxidative atmospheres. A significant reduction of CNC thermal stability was observed only for the longest reaction time (240 min) and the highest molar ratio of SA:OH. This illustrates the possibility of manufacturing thermally stable, succinylated, CNC by controlling the reaction conditions and the degree of esterification.

scholarly journals Improved Hydrophobicity of Macroalgae Biopolymer Film Incorporated with Kenaf Derived CNF Using Silane Coupling Agent

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2254
Author(s):  
Adeleke A. Oyekanmi ◽  
N. I. Saharudin ◽  
Che Mohamad Hazwan ◽  
Abdul Khalil H. P. S. ◽  
Niyi G. Olaiya ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Cellulose Nanofibrils ◽  
Hydroxyl Groups ◽  
Water Contact ◽  
Silane Coupling ◽  
Cnf Films ◽  
Kenaf Bast ◽  
Thermal Stability Of

Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films’ modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.

Enhanced Thermal Stability of Esterified Lignin in Different Solvent Mediums

2018 ◽  
Vol 9 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Sharifah Nurul Ain Syed Hashim ◽  
Sarani Zakaria ◽  
Chin Hua Chia ◽  
Sharifah Nabihah Syed Jaafar
Keyword(s):  
Thermal Stability ◽  
Alkaline Solution ◽  
Room Temperature ◽  
Hydroxyl Groups ◽  
Aqueous Alkaline Solution ◽  
Alkali Lignin ◽  
Weight Percentage ◽  
H Nmr ◽  
Ft Ir ◽  
Thermal Stability Of

In this study, soda alkali lignin from oil palm empty fruit bunch (EFB-AL) and kenaf core (KC-AL) are esterified with maleic anhydride under two different conditions, namely i) pyridine at temperature of 120°C for 3h and ii) aqueous alkaline solution at room temperature for 4h. As a result, the weight percentage gain (WPG) of the esterified EFB-AL (EFB-EL) and esterified KC-AL (KC-EL) in pyridine demonstrated a higher compared to aqueous alkaline solution. The FT-IR results of EFB-EL and KC-EL in both solvents exhibited some changes at the carbonyl and hydroxyl groups. Furthermore, the esterification process induced the carboxylic peak to appear in both alkali lignin samples. The outcome is confirmed by conducting H-NMR analysis, which demonstrated ester and carboxylic acid peaks within the spectral analysis. Finally, the TGA results showed both EFB-EL and KC-EL that are exposed to aqueous alkaline actually possessed better thermal stability and higher activation energy (Ea) compared to the esterified samples in pyridine.

Preparation and Thermal Properties of High-Purified Molten Nitrate Salt Materials with Heat Transfer and Storage

2015 ◽  
Vol 34 (8) ◽  
Author(s):  
Hongtao Zhang ◽  
Youjing Zhao ◽  
Jingli Li ◽  
Lijie Shi ◽  
Min Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Stability ◽  
Thermal Properties ◽  
Molten Salts ◽  
Operating Temperature ◽  
Nitrate Salt ◽  
Solar Salt ◽  
And Storage ◽  
Thermal Stability Of ◽  
Operating Temperature Range

AbstractThis paper focuses on thermal stability of molten salts, operating temperature range and latent heat of molten salts at a high temperature. In this experiment, multi-component molten salts (purified Solar Salt) composed of purified NaNO

scholarly journals The Thermal Properties of Polyurethane/Neoprene Blends on Prosthetic Foot

2020 ◽  
Vol 990 ◽  
pp. 106-110
Author(s):  
Mohd Zulkifli Mohamad Noor ◽  
Mohamad Anas Mohd Azmi ◽  
Mohd Shaiful Zaidi Mad Desa ◽  
Mohd Bijarimi Mat Piah ◽  
Azizan Ramli
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Low Cost ◽  
Decomposition Temperature ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Prosthetic Foot ◽  
Reinforced Polymer ◽  
New Material ◽  
Thermal Stability Of

Neoprene reinforced polymer has become an attraction in current research and development of new material blend. In this invention, neoprene was chosen to be enhance to polyurethane because of their superior properties that possess extraordinary mechanical, electrical, optical and thermal properties on prosthetic foot. In this research, polyurethane was chosen due to good rigidity, easy processing and low cost. The reinforcement polyurethane with neoprene is expected to improve the properties of polyurethane. The objective of this research was conducted to investigate the effect of neoprene contents on thermal properties of polyurethane reinforced neoprene on prosthetic foot. The effect of neoprene on thermal properties neoprene reinforced polyurethane was analysed in term of its thermal stability by thermal gravimetric analysis (TGA). Moreover, the visual of small topographic details on the surface of polyurethane/neoprene blends will be examined by scanning electron microscope (SEM). Based on result, the thermal properties show the great enhancement at high neoprene contents which is 1.0wt%. The thermal stability of polyurethane reinforced neoprene improves when the temperature where decomposition starts to occurs are higher than decomposition temperature of pure polyurethane. Then, thermal conductivity of polyurethane shows the great improvement after the addition of neoprene. Lastly, the smooth surface and visible of sheets pattern on surface represent the present of neoprene disperse into polymer that enhance brittleness. Thus, the presence of neoprene has clearly enhanced the thermal stability of the polyurethane. Table 1 shows formulation of neoprene and polyurethane.

Epoxy Cured with Anhydride Terminated Polydimethylsiloxane: Cure Kinetics and Thermal Properties

2011 ◽  
Vol 415-417 ◽  
pp. 261-264
Author(s):  
Yuan Ren ◽  
Zheng Xi ◽  
Wen Jun Gan ◽  
Liang Zhang ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Thermal Properties ◽  
Succinic Anhydride ◽  
Cure Kinetics ◽  
Diglycidyl Ether ◽  
Scanning Calorimetry ◽  
Thermogravimetric Analyses ◽  
Isothermal Measurements ◽  
Thermal Stability Of

A siloxane-containing dianhydride, succinic anhydride terminated polydimethylsiloxane (DMS-Z21) was selected to cure diglycidyl ether of bisphenol-A based epoxy resin (DGEBA). The cure kinetics and thermal properties were investigated by nonisothermal and isothermal differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA), respectively. The activation energy (Ea) of the curing reaction was obtained based on the methods of Kissinger and isothermal measurements. The results of the thermogravimetric analyses of the DGEBA/DMS-Z21 system showed that the thermal stability of the DGEBA/DMS-Z21 system was slightly higher than the DGEBA/MeTHPA system.

Morphology, Mechanical and Thermal Properties of Poly(Lactic Acid)/Propylene-Ethylene Copolymer/Cellulose Composites

2019 ◽  
Vol 972 ◽  
pp. 172-177
Author(s):  
Sirirat Wacharawichanant ◽  
Patteera Opasakornwong ◽  
Ratchadakorn Poohoi ◽  
Manop Phankokkruad
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Tensile Stress ◽  
Cellulose Fibers ◽  
Phase Morphology ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Ethylene Copolymer ◽  
Thermal Stability Of

This work studied the effects of various types of cellulose fibers on the morphology, mechanical and thermal properties of poly(lactic acid) (PLA)/propylene-ethylene copolymer (PEC) (90/10 w/w) blends. The PLA/PEC blends before and after adding cellulose fibers were prepared by melt blending method in the internal mixer and molded by compression method. The morphological analysis observed that the presence of cellulose in PLA did not change the phase morphology of PLA, and PLA/cellulose composite surfaces were observed the cellulose fibers inserted in PLA matrix and fiber pull-out. The phase morphology of PLA/PEC blends was changed from brittle fracture to ductile fracture behavior and showed the phase separation between PLA and PEC phases. The presence of celluloses did not improve the compatibility between PLA and PEC phases. The tensile stress and strain curves found that the tensile stress of PLA was the highest value. The addition of all celluloses increased Young’s modulus of PLA. The PEC presence increased the tensile strain of PLA over two times when compared with neat PLA and PLA was toughened by PEC. The incorporation of cellulose fibers in PLA/PEC blends could improve Young’s modulus, tensile strength, and stress at break of the blends. The thermal stability showed that the degradation temperatures of all types of cellulose were less than the degradation temperatures of PLA. Thus, the incorporation of cellulose in PLA could not enhance the thermal stability of PLA composites and PLA/PEC composites. The degradation temperature of PEC was the highest value, but it could not improve the thermal stability of PLA. The incorporation of cellulose fibers had no effect on the melting temperature of the PLA blend and composites.

Effects of Microcrystalline Cellulose on the Thermal Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

2011 ◽  
Vol 284-286 ◽  
pp. 1778-1781 ◽  
Author(s):  
Zhe Zhou ◽  
Hou Yong Yu ◽  
Mei Fang Zhu ◽  
Zong Yi Qin
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Microcrystalline Cellulose ◽  
Crystallization Temperature ◽  
Solvent Casting ◽  
Melt Crystallization ◽  
Casting Method ◽  
Nucleation Agent ◽  
Tga And Dsc ◽  
Thermal Stability Of

The composites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with different microcrystalline cellulose (MCC) contents were prepared by a solvent casting method. The effects of MCC on the thermal properties of PHBV were studied by TGA and DSC. The DSC results showed that the melt crystallization temperature of the PHBV/MCC increased from 41.9 °C for PHBV to 59.8 °C for the composites containing 20 wt. % MCC, which indicated that the crystallization of PHBV became easier with the addition of MCC. It also illustrated that the MCC could be used as an effective nucleation agent for the crystallization of PHBV. Moreover, it was found that the thermal stability of the PHBV/MCC composites increased compared with the neat PHBV.

Luminescent and Thermal Properties of Eu3+ Complex with Salicylic Acid and o-Phenanthroline Trapped in Sol–Gel Glass

2011 ◽  
Vol 239-242 ◽  
pp. 294-297
Author(s):  
Cun Jin Xu ◽  
Qun Lü ◽  
Hai Ke Feng
Keyword(s):  
Thermal Stability ◽  
Salicylic Acid ◽  
Thermal Properties ◽  
Silica Gel ◽  
Sol Gel ◽  
Silica Matrix ◽  
Emission Lines ◽  
Excitation Spectra ◽  
Thermal Stability Of ◽  
Luminescence Behavior

A ternary Eu(III) complex with salicylic acid (Hsal) ando-phenanthroline (phen) was synthesized and then incorporated into silica matrix by sol-gel method. The luminescence behavior of the complex in silica gel was studied compared with that of the pure complex by means of emission, excitation spectra and thermogravimetic analysis. The results indicate that the complex Eu(sal)3(phen) in silica gel shows fewer emission lines than pure Eu(sal)3(phen) and the luminescence intensity ratio of the5D0→7F2transition to the5D0→7F1transition is lower than that of the latter. The thermal stability of Eu(sal)3(phen) is enhanced greatly through the introduction of the complex into silica matrix.

Study on the thermal stability of Controlled Permeability Formwork

2011 ◽  
Vol 374-377 ◽  
pp. 1426-1429
Author(s):  
Xiao Meng Guo ◽  
Jian Qiang Li ◽  
Xian Sen Zeng ◽  
De Dao Hong
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Dynamic Mechanical Analysis ◽  
Thermo Gravimetric Analysis ◽  
Mechanical Analysis ◽  
Gravimetric Analysis ◽  
Construction Work ◽  
Thermo Gravimetric ◽  
Excellent Thermal Stability ◽  
Thermal Stability Of

In this study, the thermal properties of a kind of new geotextile materials, so called controlled permeable formwork (CPF), were studied. Thermo-gravimetric analysis showed that the weight of CPF didn’t change much between 0~350 °C. Dynamic mechanical analysis showed that the storage modulus of CPF reduced from 25 MPa to around 10 MPa when the temperature rose to above 100 °C. The strength of sample decreased slightly with the increase of the temperature. The breaking elongation changed slightly with a maximum at 80 °C. The CPF showed excellent thermal stability and was suitable for general use in construction work.

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