Effect of Inhomogeneous Structure of Polybenzoxazine on Mechanical and Thermal Properties

2012 ◽  
Vol 562-564 ◽  
pp. 43-46
Author(s):  
Chun Ling Xin ◽  
Gang Li ◽  
Xiao Ping Yang ◽  
Ya Dong He
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Phenol Formaldehyde ◽  
Flexural Modulus ◽  
Crosslinking Density ◽  
Inhomogeneous Structure ◽  
Resin Matrix ◽  
Mechanical And Thermal Properties ◽  
Hard Phase ◽  
Soft Phase

Polybenzoxazine was one of the most widely employed matrix for advanced composites, due to their low viscosity, good dimensional stability, high glass transition temperature (Tg) and wide molecular design flexibility. To obtain high perfomance resin matrix, a fundamental understanding of the formation of crosslinking network structure and the relationship between structure and properties was essential. Therefore, the blends of benzoxazine precursor with different functionality were designed to achieve various network molecular architectures, and the effects of inhomogeneous structure of polybenzoxazine on mechanical and thermal properties were investigated. The bifunctional benzoxazine precursor (BA-a) based on bisphenol-A, formaldehyde and aniline, and the monofunctional benzoxazine monomer (Ph-a) based on phenol, formaldehyde and aniline were synthesized respectively. The blends of BA-a and Ph-a, in which the mole ratio was 1:0, 2:1, 1:1 and 1:2, repectively, were thermally cured through ring-opening reaction to obtain polybenzoxazines with various network structures. The fracture surface morphology of various polybenzoxazines was observed by atomic force microscopy (AFM). The hard phase with highly crosslinking density was dispersed in the soft phase with slightly crosslinking density, which led to the generation of inhomogeneous structure of polybenzoxazine. Dynamic mechanical thermal analysis (DMTA) of carbon fiber reinforced polybenzoxazine showed two glass transition temperatures (Tg), which corresponded to the soft phase and hard phase, respectively.With increasing the mole ratio of Ph-a, the increase of hard phase resulted in the enahncement of flexural modulus of polybenzoxazine, whereas the tensile and flexural strength of polybenzoxazine decreased due to the reduction of the crosslinking density of soft phase. Derivative thermogravimetric (DTG) analysis exhibited three major degradation steps, which characterized the decomposition, weight-loss and charring, respectively. Thermogravimetric analysis (TGA) showed that the onset degradation temperature and char yield at 850 oC increased with the increase of Ph-a mole ratio, indicating higher thermal stability and lower decomposition rate, which was attributed to the increase of hard phase with highly crosslinking density.

Mechanical and Thermal Properties of Epoxy Composites Containing Amine-Modified Silica Nanoparticles

2017 ◽  
Vol 737 ◽  
pp. 262-268
Author(s):  
Hye Ryun Lee ◽  
Moon Il Kim ◽  
Hye Ryun Na ◽  
Choong Sun Lim ◽  
Bong Kuk Seo
Keyword(s):  
Tensile Strength ◽  
Glass Transition ◽  
Thermal Properties ◽  
Silica Nanoparticles ◽  
Flexural Modulus ◽  
Silica Particles ◽  
Test Machine ◽  
Mechanical And Thermal Properties ◽  
Modified Silica ◽  
Modified Silica Nanoparticles

Epoxy/silica composites were prepared using aminopropyl triethoxysilane (APTES)-modified silica nanoparticles in the sol state. Different sizes of silica particles were synthesized and they were applied into the epoxy/silica composites with different compositions. The mechanical and thermal properties of the composites were investigated and compared with those of pristine epoxy composite. The structure and morphology of the modified silica nanoparticles and epoxy/silica composites were analyzed using field emission scanning electron microscope. The flexural modulus and tensile strength of the epoxy/silica composites were investigated by universal test machine (UTM). Also, glass transition and thermal stability were investigated using thermomechanical analyzer (TMA). Sizes of silica particles in sol state were controlled by using different concentration of the accelerator. The tensile strength of epoxy/silica composites containing 20 wt% of 30 nm silica was found to be 37.98 MPa. In addition, the glass transition temperature (Tg) decreased with increasing silica particle sizes.

IMPROVEMENT OF MECHANICAL AND THERMAL PROPERTIES OF CFRP LAMINATES USING MICRO-FIBRILLATED CELLULOSE

2012 ◽  
Vol 06 ◽  
pp. 622-627 ◽  
Author(s):  
HYOJIN KIM ◽  
TADASHI SUZUKI ◽  
KENICHI TAKEMURA
Keyword(s):  
Thermal Expansion ◽  
Glass Transition ◽  
Thermal Properties ◽  
Carbon Fiber ◽  
Coefficient Of Thermal Expansion ◽  
Flexural Modulus ◽  
Mechanical And Thermal Properties ◽  
Flexural Test ◽  
Cfrp Laminates ◽  
Carbon Fiber Epoxy

The aim of this study is improvement of mechanical and thermal properties of plain woven carbon fiber (CF) reinforced epoxy with addition of MFC as the additive. Carbon fiber/epoxy laminates with addition 0.3, 0.5, 0.7 and 1wt% of MFC were characterized by flexural test, DSC and TMA. The result represented that the flexural strength improved slightly at 0.3 and 0.5 wt% of MFC, but flexural modulus was not changed, respectively. The glass transition temperature of MFC-CFRP laminates showed the increase according to increase of MFC addition at 0.7 and 1.0 wt%. The coefficient of thermal expansion was decrease by 0.7 wt% of MFC addition.

The influence of adding long basalt fiber on the mechanical and thermal properties of composites based on poly(oxymethylene)

2018 ◽  
Vol 33 (4) ◽  
pp. 435-450 ◽  
Author(s):  
Patrycja Bazan ◽  
Stanisław Kuciel ◽  
Mariola Sądej
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Average Length ◽  
Flexural Modulus ◽  
Basalt Fiber ◽  
Charpy Impact ◽  
Mechanical And Thermal Properties ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Atr Spectroscopy

The work has evaluated the possibility of the potential reinforcing of poly(oxymethylene) (POM) by basalt fibers (BFs) and influence of BFs addition on thermal properties. Two types of composites were produced by injection molding. There were 20 and 40 wt% long BFs content with an average length of 1 mm. The samples were made without using a compatibilizer. In the experimental part, the basic mechanical properties (tensile strength, modulus of elasticity, strain at break, flexural modulus, flexural strength, and deflection at 3.5% strain) of composites based on POM were determined. Tensile properties were also evaluated at three temperatures −20°C, 20°C, and 80°C. The density and Charpy impact of the produced composites were also examined. The influence of water absorption on mechanical properties was investigated. Thermal properties were conducted by the differential scanning calorimetry, thermal gravimetric analysis, and fourier transform infrared (FTIR)-attenuation total reflection (ATR) spectroscopy analysis. In order to make reference to the effects of reinforcement and determine the structure characteristics, scanning electron microscopy images were taken. The addition of 20 and 40 wt% by weight of fibers increases the strength and the stiffness of such composites by more than 30–70% in the range scale of temperature. Manufactured composites show higher thermal and dimensional stability in relation to neat POM.

High-performance polymer composites with enhanced mechanical and thermal properties from cyanate ester/benzoxazine resin and short Kevlar/glass hybrid fibers

2018 ◽  
Vol 31 (6) ◽  
pp. 719-732 ◽  
Author(s):  
Abdeldjalil Zegaoui ◽  
Mehdi Derradji ◽  
Abdul Qadeer Dayo ◽  
Aboubakr Medjahed ◽  
Hui-yan Zhang ◽  
...  
Keyword(s):  
Thermal Properties ◽  
High Performance ◽  
Hybrid Composites ◽  
Glass Fibers ◽  
Functional Materials ◽  
Polymeric Materials ◽  
Cyanate Ester ◽  
Resin Matrix ◽  
Mechanical And Thermal Properties ◽  
Hybrid Fibers

The investigation and design of new polymeric materials with an astonishing combination of properties are nowadays of great importance to facilitate the manufacturing process of high-quality products intended to be utilized in different applications and technical fields. For this intent, novel high-performance blend composites composed of the cyanate ester/benzoxazine resin blend reinforced by different proportions of silane-surface modified Kevlar and glass fibers were successfully fabricated by a compression molding technique and characterized by different experimental tests. The mechanical test results revealed that the bending and impact strength properties were considerably improved when increasing the amount of the hybrid fibers. The studied materials also presented excellent thermal stabilities as compared to the unfilled blend’s properties. With respect to the properties of the reinforcing systems, these improvements seen in either the mechanical or thermal properties could be due to the good dispersion as well as excellent adhesion of the reinforcing fibers inside the resin matrix, which were further evidenced by the Fourier transform infrared spectroscopy and scanning electron microscopy results. Consequently, the improved mechanical and thermal properties promote the use of the fabricated hybrid composites in domestic and industrial applications requiring functional materials with advanced properties for aerospace and military applications.

Studies on Mechanical and Thermal Properties of Epoxy Resin Modified by Fluorine-Containing Silicone

2013 ◽  
Vol 401-403 ◽  
pp. 713-716
Author(s):  
Cheng Fang ◽  
Dong Bo Guan ◽  
Wei Guo Yao ◽  
Shou Jun Wang ◽  
Hui An
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Epoxy Resin ◽  
Bending Strength ◽  
Mechanical And Thermal Properties ◽  
Curing Agent ◽  
Epoxy System ◽  
Resin Curing ◽  
The Impact ◽  
Modified Epoxy

The epoxy resin was modified with the mixture of α,ω-dihydroxy poly-(3,3,3-trifluoropropyl) siloxane (PTFPMS), KH560 and stannous octoate. KH560 can react with PTFPMS and also epoxy resin curing agent. The two reactions were characterized by FI-IR. The modified epoxy resin was characterized by FI-IR. The result showed that fluorine-containing silicone had been successfully introduced into the epoxy system. The mechanical and thermal properties of the modified epoxy resin were analyzed. The results showed that with the increase of PTFPMS the impact strength of epoxy resin increased, hardness and bending strength correspondingly reduced, slight decrease in the glass transition temperature.

HIGH-IMPACT PP NANOCOMPOSITES: INFLUENCE OF CLAY CONTENT ON MECHANICAL AND THERMAL PROPERTIES

2013 ◽  
Vol 12 (06) ◽  
pp. 1350039
Author(s):  
L. G. FURLAN ◽  
RICARDO V. B. OLIVEIRA ◽  
ANDRÉIA C. E. MELLO ◽  
SUSANA A. LIBERMAN ◽  
MAURO A. S. OVIEDO ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Impact Strength ◽  
Flexural Modulus ◽  
Clay Content ◽  
Mechanical Analysis ◽  
High Impact ◽  
Mechanical And Thermal Properties ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Izod Impact

The preparation of high-impact polypropylene nanocomposites with different organo-montmorillonite (O-MMT) contents by means of meltprocessing was investigated. The nanocomposite properties were evaluated by transmission electron microscopy (TEM), flexural modulus, izod impact strength, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It was noticed that the PP/O-MMT nanocomposites properties were affected by clay content. Exceptional improvements in impact strength were obtained (maximum of 185%) by the use of low O-MMT content. The results showed that higher enhancement on mechanical/thermal properties was obtained by 3 wt.% of O-MMT instead of higher quantities.

Mechanical and Thermal Properties of Oil Palm Empty Fruit Bunch-Filled Unplasticized Poly (Vinyl Chloride) Composites

2005 ◽  
Vol 13 (6) ◽  
pp. 607-617 ◽  
Author(s):  
A. Abu Bakar ◽  
A. Hassan ◽  
A.F. Mohd Yusof
Keyword(s):  
Thermal Properties ◽  
Vinyl Chloride ◽  
Oil Palm ◽  
Flexural Modulus ◽  
Degradation Process ◽  
Decomposition Temperature ◽  
Natural Fibre ◽  
Mechanical And Thermal Properties ◽  
Empty Fruit Bunches ◽  
Poly Vinyl Chloride

Awareness of the advantages of natural fibres has stimulated interest in their use to reinforce polymers. One type of natural fibre that is of great relevance to Malaysia is oil palm empty fruit bunches (EFB). To produce EFB-filled unplasticized poly(vinyl chloride) (PVC) composites, PVC resin and the various additives were first dry-blended using a laboratory blender before being milled into sheets on a two-roll mill. Test specimens were then hot pressed, after which the mechanical and thermal properties were determined. Four untreated EFB fibre contents were employed, 10, 20, 30 and 40 phr. The increase in EFB fibre content resulted in an improvement in flexural modulus at the expense of impact strength and flexural strength. The incorporation of EFB slightly enhanced the glass transition temperature but it decreased the thermal stability of the composites, evidenced by a decrease in decomposition temperature and a change in the degradation process from two to three stages.

Influence of water absorption on mechanical properties and glass transition temperatures of polyamide6/hexagonal boron nitride composites

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kawaljit Singh Randhawa ◽  
Ashwin Patel
Keyword(s):  
Glass Transition ◽  
Thermal Properties ◽  
Hexagonal Boron Nitride ◽  
Water Molecules ◽  
Mechanical And Thermal Properties ◽  
Transition Temperatures ◽  
Glass Transition Temperatures ◽  
Content Type ◽  
Environmental Humidity ◽  
Influence Of Water

PurposeThe absorption of moisture/water can affect the mechanical and thermal properties of polymers and polymer composites as many polymers, mainly polyamide thermoplastics, are sensitive to environmental humidity and can absorb a large amount of moisture. This paper investigates the effect of water molecules' absorption on mechanical and thermal properties of polyamide6/hexagonal boron nitride (PA6/h-BN) composites.Design/methodology/approachThe PA6/h-BN composites were exposed to an open environment and water for 15 days to analyse the effect of humidity/water molecules' absorption on mechanical and thermal properties. The tensile strength, hardness and impact strength of materials were measured and compared. The scanning electron microscopy (SEM), x-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses were utilized to see the influence of water absorption on microstructure, crystallinity and glass transition temperatures.FindingsAfter exposing materials to an open environment and water, the tensile strength and hardness were found to decline, while improvement in impact strength was noticed. SEM characterization revealed the formation of voids/pockets in water-immersed materials. DSC analysis revealed the loss in glass transition temperatures, and XRD analysis revealed the loss in crystallinity of water-immersed materials.Originality/valueEnvironmental conditions vary according to the geographical areas, and it varies in many countries throughout the year. Polyamides are sensitive to the environmental humidity and can absorb a large amount of moisture from the environment. It becomes necessary to test these materials in their original working conditions, and sometimes it is mandatory to see the effects of extreme environmental conditions on a component. In this article, efforts have been made to investigate the influence of extreme humidity/water conditions on thermo-mechanical properties of PA6/h-BN composites.

Evaluation of Influence of the Addition Nanofillers on the Mechanical and Thermal Properties Terpolymers Ester-Ether-Amide

2014 ◽  
Vol 59 (1) ◽  
pp. 237-239
Author(s):  
A. Kozłowska ◽  
M. Piatek-Hnat
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Thermal Properties ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Thermoplastic Elastomer ◽  
Nanocomposite Materials ◽  
Polymeric Matrix ◽  
Mechanical And Thermal Properties ◽  
Positive Effect

Abstract The results of studies of mechanical and thermal properties of synthesized elastomeric nanocomposites have been presented. An elastomeric multiblock terpoly(ester-b-ether-b-amide)s as polymeric matrix and nanoparticles SiO2 i TiO2 used as fillers. It was shown that the introduction of multiblock thermoplastic elastomer matrix of SiO2 and TiO2 nanoparticles allows to obtain nanocomposite materials with improved mechanical properties compared to the terpolymer before modification. An increase in glass transition temperature, which has a positive effect for the processing of terpolymers.

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