Curing characteristics, kinetics, and thermal properties of multifunctional fluorene benzoxazines containing hydroxyl groups

2020 ◽  
Vol 138 (13) ◽  
pp. 50131
Author(s):  
Xuan‐Yu He ◽  
Ting Wang ◽  
Zhong‐Cheng Pan ◽  
Abdul Qadeer Dayo ◽  
Jun Wang ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Hydroxyl Groups ◽  
Curing Characteristics

scholarly journals Self-Toughening and Self-Enhancement Poly(arylene ether nitrile) with Low Dielectric Constant by Solid Crosslinking Reaction

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1403 ◽  
Author(s):  
Lifen Tong ◽  
Xiting Lei ◽  
Guangyao Yang ◽  
Xiaobo Liu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Dielectric Constant ◽  
Thermal Properties ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Cross Linking ◽  
Hydroxyl Groups ◽  
Crosslinking Reaction ◽  
Arylene Ether

A novel poly(arylene ether nitrile) terminated with hydroxyl groups (PEN–OH) was synthesized successfully. The effects of heat-treatment temperature on the thermal properties, mechanical properties, and dielectric properties of the PEN–OH films were studied in detail. Due to the cross-linking reaction occurring, at high temperature, among the nitrile groups on the side of the PEN–OH main chain to form a structurally stable triazine ring, the structure of materials changes from a linear structure to a bulk structure. Thus, the thermal properties and mechanical properties were improved. In addition, the occurrence of cross-linking reactions can reduce the polar groups in the material, leading to the decrease of dielectric constant. As the heat-treatment temperature increased, the glass-transition temperature increased from 180.6 °C to 203.6 °C, and the dielectric constant decreased from 3.4 to 2.8 at 1 MHz. Proper temperature heat-treatment could improve the tensile strength, as well as the elongation, at the break of the PEN–OH films. Moreover, because of the excellent adhesive property of PEN–OH to copper foil, a double-layer flexible copper clad laminate (FCCL) without any adhesives based on PEN–OH was prepared by a simple hot-press method, which possessed high peel strength with 1.01 N/mm. Therefore, the PEN–OH has potential applications in the electronic field.

Effect of Coal Structure on Mechanical and Thermal Properties of Coal Filled Soy Protein Composites

2011 ◽  
Vol 236-238 ◽  
pp. 288-291
Author(s):  
Guang Heng Wang ◽  
An Ning Zhou
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Soy Protein ◽  
Water Resistance ◽  
Group Analysis ◽  
Surface Functional Group ◽  
Hydroxyl Groups ◽  
Mechanical And Thermal Properties ◽  
Coal Rank ◽  
Coal Structure

Using different rank coals as filler, coal-soy protein isolate (SPI) composites were prepared by compression molding processing using glycerol as plasticizer. The structure of the coals used were characterized by Fourier transform infrared (FTIR), ultimate analysis, and surface functional group analysis. The effects of coal structure on the mechanical properties, water resistance, and thermal properties were investigated. The results showed that, in different rank coals, the atomic ratio of oxygen to carbon, carboxylic acid groups, phenolic hydroxyl groups, lactone bonds, and aliphatic chains decreased with coal rank. The strength, water resistance, and glass transition temperature of coal-SPI composites decreased with coal rank. Lower ran coal filler with more reactive functional groups caused the composites strong but brittle. While, higher rank coals provide poor mechanical properties for the composites.

scholarly journals Examining the effect of hydroxyl groups on the thermal properties of polybenzoxazines: using molecular design and Monte Carlo simulation

RSC Advances ◽  
2018 ◽  
Vol 8 (32) ◽  
pp. 18038-18050 ◽  
Author(s):  
Kan Zhang ◽  
Lu Han ◽  
Yijing Nie ◽  
Matthew Louis Szigeti ◽  
Hatsuo Ishida
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Thermal Properties ◽  
Monte Carlo Simulations ◽  
Molecular Interactions ◽  
Molecular Design ◽  
Hydroxyl Groups ◽  
Structure Property ◽  
First Report ◽  
Structure Property Relationship

This article is the first report on understanding the structure-property relationship between molecular interactions and thermal properties of polybenzoxazines by Monte Carlo simulations.

scholarly journals Composites of Unsaturated Polyester Resins with Microcrystalline Cellulose and Its Derivatives

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 62 ◽  
Author(s):  
Artur Chabros ◽  
Barbara Gawdzik ◽  
Beata Podkościelna ◽  
Marta Goliszek ◽  
Przemysław Pączkowski
Keyword(s):  
Thermal Properties ◽  
Flexural Strength ◽  
Microcrystalline Cellulose ◽  
Unsaturated Polyester ◽  
Hydroxyl Groups ◽  
Resin Composites ◽  
Polyester Resins ◽  
Unsaturated Polyester Resins ◽  
Hydrophilic Character

The paper investigates the properties of unsaturated polyester resins and microcrystalline cellulose (MCC) composites. The influence of MCC modification on mechanical, thermomechanical, and thermal properties of obtained materials was discussed. In order to reduce the hydrophilic character of the MCC surface, it was subjected to esterification with the methacrylic anhydride. This resulted in hydroxyl groups blocking and, additionally, the introduction of unsaturated bonds into its structure, which could participate in copolymerization with the curing resin. Composites of varying amounts of cellulose as a filler were obtained from modified MCC and unmodified (comparative) MCC. The modification of MCC resulted in obtaining composites characterized by greater flexural strength and strain at break compared with the analogous composites based on the unmodified MCC.

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.

ANALYSIS OF THE INFLUENCE OF THE NATURE OF THE FILLER SURFACE ON THE PROPERTIES OF HYBRID ORGANIC-INORGANIC NANOCOMPOSITES BASED ON EPOXY OLIGOMER

2021 ◽  
Vol 43 (3) ◽  
pp. 190-197
Author(s):  
V.D. MYSHAK ◽  
◽  
V.V. SEMINOG ◽  
N.V. KOZAK ◽  
◽  
...  
Keyword(s):  
Thermal Properties ◽  
Chemical Nature ◽  
Epoxy Oligomer ◽  
Sorption Process ◽  
Hydroxyl Groups ◽  
Epoxy Nanocomposites ◽  
Filler Surface ◽  
Highly Dispersed ◽  
Inorganic Nanocomposites ◽  
Epoxy Groups

The aim of this work was to investigate the influence of the chemical nature of the filler surface on the properties of hybrid organo-inorganic nanocomposites based on epoxy oligomer ED-20 in the presence of nanoscale functional filler of inorganic origin - aerosil, with different surface nature. The influence of the chemical nature of the surface of highly dispersed aerosil on the thermal properties of nanocomposites based on epoxy oligomer ED-20 has been studied. The peculiarities of the process of thermooxidative destruction have been studied. It is shown that the introduction of highly dispersed aerosil in the amount of 0.5% in the epoxy matrix does not lead to changes in the thermal properties of composites, and the nanofiller in the amount of 5% improves thermal stability of composites. The kinetics of the curing process of epoxy nanocomposites was studied by IR-spectroscopy. The influence of the presence of functional groups on the nanofiller surface on rate and the degree of conversion of epoxy groups was determined. The presence of hydroxyl groups on the surface of A-300 contributes to the rate of conversion of epoxy groups to a greater extent, compared with aerosil with a modified surface, which contains on the surface methyl groups capable of blocking reactive groups. It is established that the rate of conversion of epoxy groups in the presence of aerosil decreases in the range of ED-20 > ED-20 + A-300 > ED-20 + AM-300. The sorption properties of epoxy nanocomposites have been studied. It is established that the sorption process proceeds at a higher rate when the matrix is filled with unmodified aerosil. The mechanism of influence of the chemical nature of the filler surface and content on formation and properties of epoxy nanocomposites is discussed.

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.

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