scholarly journals The influence of stereochemistry on the reactivity of the Diels–Alder cycloaddition and the implications for reversible network polymerization

2019 ◽  
Vol 10 (4) ◽  
pp. 473-485 ◽  
Author(s):  
Audrey Cuvellier ◽  
Robrecht Verhelle ◽  
Joost Brancart ◽  
Bram Vanderborght ◽  
Guy Van Assche ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Polymer Network ◽  
Diels Alder ◽  
Thermal Stability Of

The differences in reactivity and thermal stability of the stereoisomers define the thermal properties and responsiveness of the reversible polymer network.

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.

scholarly journals Mechanical, thermal and surface properties of polyacrylamide/dextran semi-interpenetrating network hydrogels tuned by the synthesis temperature

2013 ◽  
Vol 11 (2) ◽  
pp. 248-258 ◽  
Author(s):  
Maria Dinu ◽  
Maria Cazacu ◽  
Ecaterina Drăgan
Keyword(s):  
Thermal Stability ◽  
Polymer Network ◽  
Synthesis Temperature ◽  
Water Vapor Sorption ◽  
Interpenetrating Polymer Network ◽  
Vapor Sorption ◽  
Interpenetrating Network ◽  
Preparation Temperature ◽  
Thermal Stability Of ◽  
Network Morphology

AbstractThe mechanical, rheological, thermal, and surface behaviors of three polyacrylamide/dextran (PAAm/Dx) semi-interpenetrating polymer network (semi-IPN) hydrogels, prepared at 22°C, 5°C and −18°C, were investigated. The results were compared with those obtained on cross-linked PAAm without Dx synthesized under the same conditions. Hydrogels prepared at the lowest temperature were the most mechanically stable. The thermal stability of the semi-IPN hydrogels is slightly lower than the corresponding PAAm gels, irrespective of preparation temperature. The water vapor sorption capacity depended on the presence of Dx as well as preparation temperature, which determines the network morphology.

Effects of Kenaf and Rice Husk on Thermal Properties of Kenaf/CaCO3/HDPE and Rice Husk/CaCO3/HDPE Hybrid Composites

2013 ◽  
Vol 748 ◽  
pp. 201-205
Author(s):  
Abd Aziz Noor Zuhaira ◽  
Rahmah Mohamed
Keyword(s):  
Thermal Stability ◽  
Thermal Properties ◽  
Rice Husk ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Degree Of Crystallinity ◽  
Differential Scanning Calorimetric ◽  
Kenaf Fiber ◽  
Twin Screw ◽  
Thermal Stability Of

In this research, rice husk and kenaf fiber were compounded with calcium carbonate (CaCO3)/high density polyethylene (HDPE) composite.Different loadings of up to 30 parts of 50 mesh sizes of rice husk particulate and kenaf fiber were compounded using twin-screw extruder with fixed 30 parts of CaCO3 fillerto produce hybrid composites of rice husk/CaCO3/HDPE and kenaf/CaCO3/HDPE.Compounded hybrid composites were prepared and tested for thermal properties. The thermal stability of the components was examined by thermogravimetricanalysis (TGA) and differential scanning calorimetric (DSC). The DSC results showed a slightly changes in melting temperature (Tm), crystallization temperature (Tc) and the degree of crystallinity (Xc) with addition of natural fiber. TGA indicates thermal stability of hybrid composite filled with kenaf or rice husk is better than unfilledCaCO3/HDPE composite.

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