Thermal properties of polybenzoxazine exhibiting improved toughness: Blending with cyclodextrin and its derivatives

2021 ◽  
pp. 095400832110130
Author(s):  
Hailong Li ◽  
Sipei Zhao ◽  
Li Pei ◽  
Zihe Qiao ◽  
Ding Han ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Hydrogen Bonds ◽  
High Performance ◽  
Practical Application ◽  
Scanning Calorimetry ◽  
Thermoset Resins ◽  
Chemical Structures ◽  
Microscopy Techniques ◽  
Fractured Surface ◽  
Scanning Electron

Polybenzoxazines are emerging as a class of high-performance thermoset polymers that can find their applications in various fields. However, its practical application is limited by its low toughness. The cyclic β-cyclodextrin and a newly synthesized derivative (β-cyclodextrin-MAH) were separately blended with benzoxazine to improve the toughness of polybenzoxazine. The results revealed that the maximum impact strength of the blend was 12.24 kJ·m−2 and 14.29 kJ·m−2 when 1 wt.% of β-Cyclodextrin and β-Cyclodextrin-MAH, respectively, were used. The strengths were 53% and 86% higher than that of pure polybenzoxazine. The curing reaction, possible chemical structures, and fractured surface were examined using differential scanning calorimetry, Fourier transform infrared spectroscopy, and scanning electron microscopy techniques to understand the mechanism of generation of toughness. The results revealed that the sea-island structure and the presence of hydrogen bonds between polybenzoxazine and β-cyclodextrin and β-cyclodextrin-MAH resulted in the generation of toughness. Furthermore, the curves generated during thermogravimetric analysis did not significantly change, revealing the good thermal properties of the system. The phase-separated structure and the hydrogen bonds present in the system can be exploited to prepare synergistically tough polybenzoxazine exhibiting excellent thermal properties. This can be a potential way of modifying the thermoset resins.

Star-shaped arylacetylene resins derived from silicon

2020 ◽  
Vol 40 (8) ◽  
pp. 676-684
Author(s):  
Niping Dai ◽  
Junkun Tang ◽  
Manping Ma ◽  
Xiaotian Liu ◽  
Chuan Li ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Mechanical Test ◽  
Flexural Modulus ◽  
Mechanical Analysis ◽  
Reinforced Composites ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Structures And Properties ◽  
High Performance Resin

AbstractStar-shaped arylacetylene resins, tris(3-ethynyl-phenylethynyl)methylsilane, tris(3-ethynyl-phenylethynyl) phenylsilane, and tris (3-ethynyl-phenylethynyl) silane (TEPHS), were synthesized through Grignard reaction between 1,3-diethynylbenzene and three types of trichlorinated silanes. The chemical structures and properties of the resins were characterized by means of nuclear magnetic resonance, fourier-transform infrared spectroscopy, Haake torque rheomoter, differential scanning calorimetry, dynamic mechanical analysis, mechanical test, and thermogravimetric analysis. The results show that the melt viscosity at 120 °C is lower than 150 mPa⋅s, and the processing windows are as wide as 60 °C for the resins. The resins cure at the temperature as low as 150 °C. The good processabilities make the resins to be suitable for resin transfer molding. The cured resins exhibit high flexural modulus and excellent heat-resistance. The flexural modulus of the cured TEPHS at room temperature arrives at as high as 10.9 GPa. Its temperature of 5% weight loss (Td5) is up to 697 °C in nitrogen. The resins show the potential for application in fiber-reinforced composites as high-performance resin in the field of aviation and aerospace.

A new class of high-performance thermoset resins using dicyanoimidazole (DCI) as crosslinking group: A key demo of synthesis, curing behavior and thermal properties

Polymer ◽  
2021 ◽  
pp. 124264
Author(s):  
Zhengzhu Zhu ◽  
Xian He ◽  
Wei Tan ◽  
Jinlang Hong ◽  
Shenjun Liao ◽  
...  
Keyword(s):  
Thermal Properties ◽  
High Performance ◽  
Curing Behavior ◽  
Thermoset Resins ◽  
New Class ◽  
Group A

scholarly journals Analysis of Bio-Based Fatty Esters PCM’s Thermal Properties and Investigation of Trends in Relation to Chemical Structures

2019 ◽  
Vol 9 (2) ◽  
pp. 225 ◽  
Author(s):  
Rebecca Ravotti ◽  
Oliver Fellmann ◽  
Nicolas Lardon ◽  
Ludger Fischer ◽  
Anastasia Stamatiou ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Phase Change ◽  
Energy Demand ◽  
Phase Change Materials ◽  
Arachidic Acid ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Fatty Esters ◽  
Latent Heat Storage ◽  
Chemical Structures

As global energy demand increases while primary sources and fossil fuels’ availability decrease, research has shifted its focus to thermal energy storage systems as alternative technologies able to cover for the mismatch between demand and supply. Among the different phase change materials available, esters possess particularly favorable properties with reported high enthalpies of fusion, low corrosivity, low toxicity, low supercooling, thermal and chemical stability as well as biodegradability and being derived from renewable feedstock. Despite such advantages, little to no data on the thermal behavior of esters is available due to low commercial availability. This study constitutes a continuation of previous works from the authors on the investigation of fatty esters as novel phase change materials. Here, methyl, pentyl and decyl esters of arachidic acid, and pentyl esters of myristic, palmitic, stearic and behenic acid are synthesized through Fischer esterification with high purities and their properties are studied. The chemical structures and purities are confirmed through Attenuated Total Reflectance Infrared Spectroscopy, Gas Chromatography coupled with Mass Spectroscopy and Nuclear Magnetic Resonance Spectroscopy, while the determination of the thermal properties is performed through Differential Scanning Calorimetry and Thermogravimetric Analysis. In conclusion, some correlations between the melting temperatures and the chemical structures are discovered, and the fatty esters are assessed based on their suitability as phase change materials for latent heat storage applications.

RETRACTED: Fabrication of Poly(Lactic Acid) Nanofibers by Cotton Candy Method

2017 ◽  
Vol 728 ◽  
pp. 193-198
Author(s):  
Rutchaneekorn Wongpajan ◽  
Supaphorn Thumsorn ◽  
Hiroyuki Inoya ◽  
Masayuki Okoshi ◽  
Hiroyuki Hamada
Keyword(s):  
Differential Scanning Calorimetry ◽  
Lactic Acid ◽  
Thermal Properties ◽  
Electron Microscope ◽  
Air Pressure ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Cotton Candy ◽  
Nozzle Temperature ◽  
Scanning Electron

The poly (lactic acid) (PLA) fiber of biodegradable polymer was fabricated by cotton candy method with small nozzle. The air pressure was varied from 0.2-0.5 MPa with nozzle temperature of 210-260°C. The morphology of fiber was determined by scanning electron microscope (SEM). Thermal properties were examined using differential scanning calorimetry (DSC). SEM results suggested that diameters the PLA fiber at temperature 250°C and air pressure of 0.2 MPa were smaller than the fiber at low and high temperature. The sizes of the fibers were lower than 1 μm and the fibers were irregular size. Crystallinity significantly decreased when increasing barrel temperatures while it slightly changed when varied air pressure. The productivity of PLA fibers was around 30-180 g/h depended on controlled the nozzle temperature and the air pressure.

Purification and characterization of kraft lignin

Holzforschung ◽  
2015 ◽  
Vol 69 (8) ◽  
pp. 943-950 ◽  
Author(s):  
Wenwen Fang ◽  
Marina Alekhina ◽  
Olga Ershova ◽  
Sami Heikkinen ◽  
Herbert Sixta
Keyword(s):  
Thermal Properties ◽  
High Performance ◽  
Inorganic Compounds ◽  
Gel Permeation Chromatography ◽  
Kraft Lignin ◽  
Hot Water ◽  
Scanning Calorimetry ◽  
Target Values ◽  
Lower Glass Transition Temperature

Abstract To upgrade the utilization of kraft lignin (KL) for high-performance lignin-based materials (e.g., carbon fiber), the purity, molecular mass distribution (MMD), and thermal properties need to be improved and adjusted to target values. Therefore, different methods, such as ultrasonic extraction (UE), solvent extraction, dialysis, and hot water treatment (HWT), were applied for the purification of KL. The chemical and thermal properties of purified lignin have been characterized by nuclear magnetic resonance, Fourier transform infrared, gel permeation chromatography, elemental analysis, differential scanning calorimetry, and thermogravimetric analysis. The lignin fractions obtained by UE with ethanol/acetone (E/A) mixture (9:1) revealed a very narrow MMD and were nearly free of inorganic compounds and carbohydrates. Further, the E/A-extracted lignin showed a lower glass transition temperature (Tg) and a clearly detectable melting temperature (Tm). Dialysis followed by HWT at 220°C is an efficient method for the removal of inorganics and carbohydrates; however, lignin was partly forming condensed structures during the treatment.

Thermal Properties and Morphology of Electrospun PEG/PVP Composite Fibers as Novel Phase Change Materials

2012 ◽  
Vol 204-208 ◽  
pp. 3998-4001
Author(s):  
Qi Song Shi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Phase Change ◽  
Phase Change Materials ◽  
Composite Fibers ◽  
Scanning Calorimetry ◽  
Ultrafine Fibers ◽  
Scanning Electron

The ultrafine fibers based on the composites of polyethylene glycol(PEG) and polyvinylpyrrolidone(PVP) were prepared successfully via electrospinning as phase change materials. The thermal properties and morphology of the composite fibers were studied by differential scanning calorimetry(DSC) and scanning electron microscopy(SEM), respectively.

Temperature-Regulating Properties of Phase Change Fiber Blended Knitted Fabrics after Laundering

2011 ◽  
Vol 393-395 ◽  
pp. 397-400
Author(s):  
Wei Lai Chen ◽  
Miao Miao He ◽  
Ying Gao ◽  
Xia Wu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Retention Rate ◽  
Cooling Process ◽  
Scanning Calorimetry ◽  
Knitted Fabrics ◽  
Dsc Analyses ◽  
Scanning Electron

In order to study the temperature- regulating properties of cotton/mercerized wool/Outlast fiber 50/10/40 blended knitted fabrics after laundering, Scanning electron microscopy (SEM) and Differential scanning calorimetry (DSC) analyses were used to test the thermal properties of the fabrics by varying washing cycles. The results show that the enthalpy of fabrics reduces with the increase of washing cycles. Enthalpy retention rate of fabrics is more than 89% after 30 cycles washing, and still above 80% after 50 cycles washing in cooling process.

Syntheses of novel benzoxazines having vinyl groups and thermal properties of the thermosets

2012 ◽  
Vol 24 (8) ◽  
pp. 765-774 ◽  
Author(s):  
Tsutomu Takeichi ◽  
Soulideth Thongpradith ◽  
Shoko Hirai ◽  
Tomomi Takiguchi ◽  
Takehiro Kawauchi
Keyword(s):  
Thermal Properties ◽  
Ring Opening ◽  
Exothermic Peak ◽  
Thermal Cure ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Chemical Structures ◽  
Polymerization Behavior ◽  
Chain Polymerization ◽  
Vinyl Group

Novel benzoxazines having vinyl groups were synthesized from phenol or bisphenol A, 3- or 4-vinylaniline and paraformaldehyde. The chemical structures of the monomers were confirmed by Fourier transform infrared and 1H-NMR analyses. The polymerization behavior of the monomers was monitored by differential scanning calorimetry. Exothermic peak of the monomers appeared in the range of 219–252 °C, due to the chain polymerization of the vinyl group and the ring-opening polymerization of benzoxazine occurring at the same temperature range. The thermal cure of the monomers afforded polybenzoxazines that have higher thermal properties than those from typical benzoxazines without vinyl groups. For example, glass transition temperature ( Tg) increased for 40 to 100 °C by the introduction of vinyl groups, the highest Tg being observed at 290 °C. The 5% weight loss temperature determined by thermogravimetric analysis also increased by the introduction of vinyl groups.

scholarly journals METHODOLOGIES FOR THE STUDY OF MORPHOLOGICAL AND THERMAL PROPERTIES OF STARCH

2018 ◽  
Vol 5 (3) ◽  
pp. 187-195
Author(s):  
Juliana Aparecida Correia Bento ◽  
Karen Carvalho Ferreira ◽  
Priscila ZaczuK Bassinello ◽  
Menandes Alves De Souza Neto
Keyword(s):  
Electron Microscopy ◽  
Thermal Properties ◽  
Food Industry ◽  
Starch Granule ◽  
Morphological Characterization ◽  
Technological Properties ◽  
Scanning Calorimetry ◽  
Main Component ◽  
Scanning Electron

Starch, a carbohydrate used as a reserve of energy in most plants, is widely used in the food industry, either as a main component or as a thickener. Considering the application of this as an ingredient in the food industry, the study of the morphological and thermal properties of this food is of great importance because it can predict its behavior during and after the processing of this. Methodologies such as scanning electron microscopy, light scattering and optical microscopy are the most used tools in the morphological characterization of the starch granule generating accurate results and good quality. Regarding the methodologies for the study of thermal properties, the rapid amylographic analyzer and the differential scanning calorimetry are the most used. The set of results obtained with these methodologies, allows to know the technological properties of the starch, characterizing them, and even to identify the origin of this one.

Preparation and Thermal Properties of Polybenzoxazine/TiC Hybrids

2014 ◽  
Vol 887-888 ◽  
pp. 49-52 ◽  
Author(s):  
Noureddine Ramdani ◽  
Jun Wang ◽  
Wen Bin Liu
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
High Performance ◽  
Phenolic Resin ◽  
Scanning Calorimetry ◽  
New Class ◽  
Solution Blending ◽  
Tic Nanoparticles ◽  
Thermal Stability Of

In this work, typical polybenzoxazine, as new class of phenolic resin, has been used as a matrix for preparing a series of high performance hybrid materials using various amounts of titanium carbide (TiC) ranging between 0-10 wt% as fillers, via a solution blending technique. The thermal properties of bisphenol A-aniline base benzoxazine monomers (BA-a) and TiC mixtures have been studied by differential scanning calorimetry (DSC). The thermal stability of their cured hybrids has been tested by means of thermogravimetric analysis (TGA). The result showed that the glass transition temperature of the prepared composites increased with increasing the amount of TiC to reach a higher value at 194°C. Also, the incorporation of TiC nanoparticles has considerably improved the thermal stability of the hybrids including the char yield which increase by 50 % at 10 wt% TiC content.

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