A UNIQUE APPROACH TO EXPERIMENTAL CHARACTERIZATION OF A THERMOSETTING POLYMER MATRIX FOR ICME FRAMEWORKS

2021 ◽  
Author(s):  
MICHAEL N. OLAYA ◽  
SAGAR PATIL ◽  
GREGORY M. ODEGARD ◽  
MARIANNA MAIARÙ

A novel approach for characterization of thermosetting epoxy resins as a function of the degree of cure is presented. Density, cure kinetics, tensile strength, and Young’s modulus are experimentally characterized across four mixing ratios of DGEBF/DETDA epoxy. Dynamic differential scanning calorimetry (DSC) is used to characterize parameters for a Prout-Thompkins kinetic model unique to each mixing ratio case through a data fitting procedure. Tensile strength and Young’s modulus are then characterized using stress-strain data extracted from quasi-static, uniaxial tension tests at room temperature. Strains are measured with the 2-D digital image correlation (DIC) optical strain measurement technique. Strength tends to increase as amine content use in the formulation increases. The converse trend is observed for Young’s modulus. Density measurements also reveal an inverse relationship with amine content.

2020 ◽  
Vol 111 (3-4) ◽  
pp. 695-709
Author(s):  
H. Gonabadi ◽  
A. Yadav ◽  
S. J. Bull

Abstract 3D printing by fused filament fabrication (FFF) provides an innovative manufacturing method for complex geometry components. Since FFF is a layered manufacturing process, effects of process parameters are of concern when plastic materials such as polylactic acid (PLA), polystyrene and nylon are used. This study explores how the process parameters, e.g. build orientation and infill pattern/density, affect the mechanical response of PLA samples produced using FFF. Digital image correlation (DIC) was employed to get full-field surface-strain measurements. The results show the influence of build orientation and infill density is significant. For on-edge orientation, the tensile strength and Young’s modulus were 55 MPa and 3.5 GPa respectively, which were about 91% and 40% less for the upright orientation, demonstrating a significant anisotropy. The tensile strength and Young’s modulus increased with increasing infill density. In contrast, different infill patterns have no significant effect. Considering the influence of build orientation, based on the experimental results, a constitutive model derived from the laminate plate theory was employed. The material parameters were determined by tensile tests. Results demonstrated a reasonable agreement between the experimental data and the predictive model. Similar anisotropy to tension was observed in shear tests; shear modulus and shear strength for 45° flat orientation were about 1.55 GPa and 36 MPa, whereas for upright specimens they were about 0.95 GPa and 18 MPa, respectively. The findings provide a framework for systematic mechanical characterisation of 3D-printed polymers and potential ways of choosing process parameters to maximise performance for a given design.


e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Sayant Saengsuwan

AbstractThe influence of annealing on the microstructure and molecular orientation, thermal behaviour and mechanical properties of uniaxially drawn iPP thin film was studied by wide-angle X-ray diffraction, differential scanning calorimetry and tensile testing, respectively. The correlations of mechanical and microstructural properties of annealed films were also examined. The transformation of smectic phase of iPP to the α-form was more pronounced with increasing annealing time and temperature. The true and apparent crystallinities and crystal thickness were strongly enhanced with annealing time and temperature. The relative molecular orientation tended to increase with annealing time. These results caused the significant improvement of modulus and tensile strength of the annealed films in both machine (MD) and transverse (TD) directions. The increases in MD-Young’s modulus and MD-tensile strength were well correlated with the increase in true crystallinity obtained in equatorial scans. Some relationship between the increase in crystal thickness and the increase in Young’s modulus in both MD and TD directions was also found.


Recycling ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 33 ◽  
Author(s):  
Job Momanyi ◽  
Michael Herzog ◽  
Peter Muchiri

Polypropylene and polystyrene are petroleum-based thermoplastics which are commonly used and disposed of in the environment after their service life, leading to environmental degradation. There is a need to recycle polypropylene and polystyrene, but the effect of recycling on thermo-mechanical properties is not well understood. This study aims to determine thermo-mechanical properties of the recycled polypropylene and recycled polystyrene and compare them with corresponding virgin polypropylene and newly produced polystyrene (general purpose polystyrene 1540 and high impact polystyrene 7240). The study was carried out by preparing bar-shaped samples of recycled polypropylene, recycled polystyrene, general purpose polystyrene 1540, and high impact polystyrene 7240 by compression molding using a hot press and thermally characterizing them to determine glass transition temperature and melting temperature using differential scanning calorimetry. The changes in Young’s modulus, tensile strength, hardness, and toughness due to recycling activities were determined at room temperature (24 °C), 40 °C, 60 °C, and 80 °C. The thermo-mechanical properties of recycled polystyrene (PS) were found to be comparable to those of high impact polystyrene (HIPS) 7240. The study revealed that the hardness and toughness for the recycled polymers were higher than those of corresponding virgin polymers. On the other hand, tensile strength and Young’s modulus for the recycled polymers were lower than those of the virgin polymers. Understanding the thermo-mechanical properties of the recycled polymers will contribute to more industrial applications hence increase the rate of recycling, resulting in a reduction in environmental pollution.


2019 ◽  
Vol 28 (8-9) ◽  
pp. 589-597
Author(s):  
Manokaran Vadivel ◽  
Moses Suresh Chandra Kumar ◽  
Jabbar Abbas Mohaideen ◽  
Muthukaruppan Alagar ◽  
Murugesan Sankarganesh ◽  
...  

Hybrid matrices (epoxidized of ethylene–propylene–diene monomer (eEPDM) -g-aminopropyltriethoxysilane (APTES)/hydroxyl terminated polydimethylsiloxane (HTPDMS)/polyurethane (PU)) were developed based on eEPDM with 3-APTES coupling agent and varying weight percentages (0.75, 1.50, 2.25, and 3.00 wt%) of PU prepolymer as coreactant using 7.5 wt% of HTPDMS as chain extender using suitable experimental conditions. The formation of hybrid matrices and their structure were characterized by Fourier transform infrared (FTIR). The thermal and morphological properties of the hybrid matrices were analyzed using differential scanning calorimetry and scanning electron microscope, respectively. Mechanical properties (tensile strength, elongation at break (%), Young’s modulus, and hardness) were characterized as per ASTM standards. Data resulted from mechanical studies, it was noticed that the incorporation of 3-APTES, HTPDMS, and PU into eEPDM has improved the elongation at break (%) and lowered the values of tensile strength, Young’s modulus, and hardness according to the percentage concentration. Morphological studies indicate the presence of heterogeneous morphology. Data obtained from different studies, it suggested that the hybrid matrices developed in the present work can be used as cable insulates for high-performance industrial and engineering applications.


2021 ◽  
Vol 11 (9) ◽  
pp. 1523-1533
Author(s):  
Yong-Ping Li ◽  
Hitoshi Takagi ◽  
Antonio N. Nakagaito ◽  
Takumi Watanabe

In order to explore the possibility of polyvinyl alcohol (PVA) reinforced by mixture of chitin nanofibers (ChNFs) and microfibrillated cellulose (MFC) instead of a single reinforcing phase, mechanical properties of PVA based hybrid nanocomposites reinforced with combination of ChNFs and MFC in various mixing ratios were investigated. For comparison, two different experiments were conducted to prepare nanocomposite films by casting technical processing, where ratios of ChNFs to MFC were mixed varying from 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, and 0:1 in both projects, while in Project 1 the weights of PVA and ChNFs were always kept constant and the weight of PVA only was kept constant in Project 2. The results were as follows: (1) The hybrid ternary nanocomposites acquired the highest Young’s modulus and tensile strength when ratio of ChNFs to MFC was 1:1, which exhibited higher Young’s modulus and higher tensile strength than PVA/ChNFs composites, but delivered higher Young’s modulus and similar tensile strength comparing to PVA/MFC composites; (2) Aggregations and voids inside nanocomposites were detrimental to mechanical properties of PVA based hybrid nanocomposites. In some industries such as food packing, PVA based hybrid nanocomposites at mixing ratio 1:1 of ChNFs to MFC are applied presumably with ChNFs partly instead of MFC in the future.


2021 ◽  
Vol 912 (1) ◽  
pp. 012073
Author(s):  
B Wirjosentono ◽  
Tamrin ◽  
A H Siregar ◽  
D A Nasution

Abstract Blending of natural rubber (NR) with epoxidised natural rubber (ENR 25) improved engineering characteristics of the blends, especially on their toughness, resistant to mineral oil, as well as their adhesion on hydrophilic surfaces, such as metals and concretes. Addition of natural microbentonite was expected not only to improve the blend’s compatibility, but also to enhance their thermal characteristics and adhesion properties on hydrophilic surfaces. In this works Indonesian natural rubbers (SIR-10) have been blended with epoxidised natural rubber (ENR-25) in a reflux rector in xylene solution with addition of various loading of natural microbentonite as fillers. Mechanical properties of the blends were characterized using tensile tests (tensile strength, elongation at break, and Young’s modulus), whereas their thermal properties were measured using differential scanning calorimetry (DSC). Furthermore, to estimate their adhesion properties on hydrophilic surfaces, the blends were immersed in water, and their water uptake were measured gravimetrically, as well as changes on their mechanical properties. It was found that optimum composition of natural microbentonite in the blend with highest tensile strength and Young’s modulus was obtained when loading of the filler was 4 phr. When compared to that without filler, DSC thermogram of the optimum blend showed better thermal properties (lower heat release decreased from 903.10 J/g to 420.17 J/g) although the decomposition temperatures did not change considerably (407.8° to 408.09°C). Whereas the later also exhibited higher water uptake (0.05 to 0.34 %) and still with acceptable mechanical properties as adhesive materials.


2013 ◽  
Vol 13 (2) ◽  
pp. 114-121 ◽  
Author(s):  
Faisal Amri Tanjung ◽  
Salmah Husseinsyah ◽  
Kamarudin Hussin ◽  
Iqmal Tahir

Effects of methyl methacrylate on the properties of chitosan-filled polypropylene (PP) composites has been investigated. Mechanical and thermal properties of the composites were analyzed according to ASTM D 638-91, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). The results showed that tensile strength of PP composites decreased upon the addition of chitosan, while Young's modulus improved. At a similar filler loading, the treated PP/chitosan composites were found to have higher tensile strength and Young's modulus as compared with the untreated composites. Thermal analysis results showed that thermal stability and crystallinity of the treated composites were higher than the untreated ones. Scanning electron microscopy (SEM) and Fourier transforms infrared (FTIR) studies revealed less detached filler from matrix on tensile surface of the treated composites as an evidence of enhanced filler-matrix interfacial adhesion due to formation of ester-bridge between the chitosan and the methyl methacrylate.


2011 ◽  
Vol 695 ◽  
pp. 170-173 ◽  
Author(s):  
Voravadee Suchaiya ◽  
Duangdao Aht-Ong

This work focused on the preparation of the biocomposite films of polylactic acid (PLA) reinforced with microcrystalline cellulose (MCC) prepared from agricultural waste, banana stem fiber, and commercial microcrystalline cellulose, Avicel PH 101. Banana stem microcrystalline cellulose (BS MCC) was prepared by three steps, delignification, bleaching, and acid hydrolysis. PLA and two types of MCC were processed using twin screw extruder and fabricated into film by a compression molding. The mechanical and crystalline behaviors of the biocomopsite films were investigated as a function of type and amount of MCC. The tensile strength and Young’s modulus of PLA composites were increased when concentration of MCC increased. Particularly, banana stem (BS MCC) can enhance tensile strength and Young’s modulus of PLA composites than the commercial MCC (Avicel PH 101) because BS MCC had better dispersion in PLA matrix than Avicel PH 101. This result was confirmed by SEM image of fractured surface of PLA composites. In addition, XRD patterns of BS MCC/PLA composites exhibited higher crystalline peak than that of Avicel PH 101/PLA composites


2012 ◽  
Vol 3 (1) ◽  
pp. 13-26
Author(s):  
Myrtha Karina ◽  
Lucia Indrarti ◽  
Rike Yudianti ◽  
Indriyati

The effect of castor oil on the physical and mechanical properties of bacterial cellulose is described. Bacterial cellulose (BC) was impregnated with 0.5–2% (w/v) castor oil (CO) in acetone–water, providing BCCO films. Scanning electron micrographs revealed that the castor oil penetrated the pores of the bacterial cellulose, resulting in a smoother morphology and enhanced hydrophilicity. Castor oil caused a slight change in crystallinity indices and resulted in reduced tensile strength and Young's modulus but increased elongation at break. A significant reduction in tensile strength and Young's modulus was achieved in BCCO films with 2% castor oil, and there was an improvement in elongation at break and hydrophilicity. Impregnation with castor oil, a biodegradable and safe plasticiser, resulted in less rigid and more ductile composites.


Author(s):  
Kyong Min Kim ◽  
Yazan Al-Zain ◽  
Akiko Yamamoto ◽  
Amirah H. Daher ◽  
Ahmad T. Mansour ◽  
...  

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