scholarly journals Poly(ε-Caprolactone)/Brewers’ Spent Grain Composites—The Impact of Filler Treatment on the Mechanical Performance

2020 ◽  
Vol 4 (4) ◽  
pp. 167
Author(s):  
Aleksander Hejna
Keyword(s):  
Chemical Structure ◽  
Mechanical Performance ◽  
Natural Fiber ◽  
Reactive Extrusion ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Interface Surface ◽  
Spent Grain ◽  
The Impact

Waste lignocellulose materials, such as brewers’ spent grain, can be considered very promising sources of fillers for the manufacturing of natural fiber composites. Nevertheless, due to the chemical structure differences between polymer matrices and brewers’ spent grain, filler treatment should be included. The presented work aimed to investigate the impact of fillers’ reactive extrusion on the chemical structure and the poly(ε-caprolactone)/brewers’ spent grain composites’ mechanical performance. The chemical structure was analyzed by Fourier-transform infrared spectroscopy, while the mechanical performance of composites was assessed by static tensile tests and dynamic mechanical analysis. Depending on the filler pretreatment, composites with different mechanical properties were obtained. Nevertheless, the increase in pretreatment temperature resulted in the increased interface surface area of filler, which enhanced composites’ toughness. As a result, composites were able to withstand a higher amount of stress before failure. The mechanical tests also indicated a drop in the adhesion factor, pointing to enhanced interfacial interactions for higher pretreatment temperatures. The presented work showed that reactive extrusion could be considered an auspicious method for lignocellulose filler modification, which could be tailored to obtain composites with desired properties.

scholarly journals Mechanical, Thermal and Rheological Properties of Polyethylene-Based Composites Filled with Micrometric Aluminum Powder

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1242
Author(s):  
Olga Mysiukiewicz ◽  
Paulina Kosmela ◽  
Mateusz Barczewski ◽  
Aleksander Hejna
Keyword(s):  
Mechanical Properties ◽  
Melt Flow Index ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Flow Index ◽  
Scanning Calorimetry ◽  
Metal Composites ◽  
Pre Treatment ◽  
The Impact ◽  
Properties Of Composites

Investigations related to polymer/metal composites are often limited to the analysis of the electrical and thermal conductivity of the materials. The presented study aims to analyze the impact of aluminum (Al) filler content (from 1 to 20 wt%) on the rarely investigated properties of composites based on the high-density polyethylene (HDPE) matrix. The crystalline structure, rheological (melt flow index and oscillatory rheometry), thermal (differential scanning calorimetry), as well as static (tensile tests, hardness, rebound resilience) and dynamic (dynamical mechanical analysis) mechanical properties of composites were investigated. The incorporation of 1 and 2 wt% of aluminum filler resulted in small enhancements of mechanical properties, while loadings of 5 and 10 wt% provided materials with a similar performance to neat HDPE. Such results were supported by the lack of disturbances in the rheological behavior of composites. The presented results indicate that a significant content of aluminum filler may be introduced into the HDPE matrix without additional pre-treatment and does not cause the deterioration of composites’ performance, which should be considered beneficial when engineering PE/metal composites.

scholarly journals Mechanical Performance Under Various Conditions of 3D Printed Polylactide Composites With Natural Fibers

2021 ◽  
Author(s):  
Karolina E. Mazur ◽  
Aleksandra Borucka ◽  
Paulina Kaczor ◽  
Szymon Gądek ◽  
Stanislaw Kuciel
Keyword(s):  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Natural Fibers ◽  
Crystallization Rate ◽  
Mechanical Tests ◽  
Hydrothermal Degradation ◽  
3D Printed ◽  
The Impact ◽  
Different Levels ◽  
Additive Methods

Abstract In the study, polylactide-based (PLA) composites modified with natural particles (wood, bamboo, and cork) and with different levels of infilling (100%, 80%, and 60%) obtained by additive methods were tested. The effect of type fiber, infill level and crystallization rate on the mechanical properties were investigated by using tensile, flexural, and impact tests. The materials were subjected to mechanical tests carried out at 23 and 80 °C. Furthermore, hydrothermal degradation was performed, and its effect on the properties was analyzed. The addition of natural fillers and different level of infilling result in a similar level of reduction in the properties. Composites made of PLA are more sensitive to high temperature than to water. The decrease in Young's modulus of PLA at 80 °C was 90%, while after 28 days of hydrodegradation ~ 9%. The addition of fibers reduced this decrease at elevated temperatures. Moreover, the impact strength has been improved by 50% for composites with cork particles and for other lignocellulosic composites remained at the same level as for resin.

scholarly journals Variability of Mechanical Properties of Collagen Membranes used in Dentistry

2018 ◽  
Vol 55 (4) ◽  
pp. 488-493
Author(s):  
Loredana Santo ◽  
Fabrizio Quadrini ◽  
Denise Bellisario ◽  
Antonella Polimeni ◽  
Anna Santarsiero
Keyword(s):  
Stress Relaxation ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Mechanical Tests ◽  
Static Behavior ◽  
Density Measurements ◽  
Dynamic Mechanical ◽  
Dependent Behavior ◽  
Order Of Magnitude ◽  
Collagen Membranes

The aim of this study is proposing a combination of measurements to assess the functional variability of collagen membranes used in Guided Bone Regeneration (GBR) and Guided Tissue Regeneration (GTR) techniques. As far as clinical applications are concerned, a proper qualification is critical when deciding, among commercially available collagen membranes, upon the most appropriate one for each specific clinical case. Two commercially available collagen membranes, namely Collprotect� and Jason�, were considered for the experimentation. After thickness and density measurements, the quasi-static behavior was studied for both membranes by means of conventional mechanical tests, i.e. tear and tensile tests, whereas their time-dependent behavior was evaluated by means of stress relaxation tests and dynamic mechanical analysis. Collagen membranes showed an elevated among samples variability. The variability within the same kind of membrane is of the same order of magnitude of the between membrane kinds variability. All the membranes showed strong time dependence both in stress relaxation and in dynamic mechanical tests. This fact should be taken under consideration for the membrane final application.

Experimental Investigations on the Influence of Temperature on the Behavior of Steel Reinforcement (Strands and Rebars)

2016 ◽  
Vol 711 ◽  
pp. 908-915
Author(s):  
Wiem Toumi Ajimi ◽  
Sylvain Chataigner ◽  
Yannick Falaise ◽  
Laurent Gaillet
Keyword(s):  
Prestressed Concrete ◽  
Temperature Increase ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Steel Reinforcement ◽  
Experimental Investigations ◽  
Tensile Behaviour ◽  
Nuclear Containment ◽  
Different Temperatures ◽  
The Impact

In the case of exceptional accidents, nuclear containment structures may be submitted to an internal temperature increase. This may have an influence on the prestressed concrete structures behavior regarding both its mechanical performance and its porosity. The presented study got interested on the impact that a temperature increase may have on the mechanical behavior of the steel reinforcement for both prestressing strands and rebars. In order to remain in realistic situations, it was chosen to study temperatures between 20°C and 140°C. Some experimental investigations regarding the tensile behaviour of steel rebars and their adherence within concrete will first be presented. Then, some investigations on steel strands will be described: some tensile tests at different temperatures, and some relaxation tests to check how the level of prestress loss may be affected by the temperature. This experimental study is part of a national French project (MACENA) aiming at assessing the impact of an accident on the behavior of nuclear containment structures. The gathered experimental data will be used for their damage assessment.

Fibre-Cement Paste Transition Zone

1994 ◽  
Vol 370 ◽  
Author(s):  
Vahan Agopyan ◽  
Holmer Savastano
Keyword(s):  
Transition Zone ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Polypropylene Fibres ◽  
Impact Performance ◽  
The Matrix ◽  
Vegetable Fibre ◽  
Electron Image ◽  
Backscattered Electron ◽  
The Impact

AbstractThe characteristics of fibres and paste of ordinary Portland cement transition zone are analysed and correlated to the mechanical properties of the produced composites. The water-cement ratio of the matrix varies from 0.30 to 0.46 and the age of the specimens varies from 7 to 180 days. Composites of vegetable fibres (coir, sisal and malva) are compared with those of chrysotile asbestos and polypropylene fibres. The analysis is made by backscattered electron image (BSEI) and energy dispersive spectroscopy (EDS). Mechanical tests evaluate the composite tensile strength and ductility.Mainly for vegetable fibre composites the transition zone is porous, cracked and rich in calcium hydroxide macrocrystals. These results are directly associated with the fibre-matrix bonding and with the composite mechanical performance. Further studies considering the impact performance of the composites compare the porosity of the transition zone with the toughness of the composites.

Effect of various enzymatic treatments on the mechanical properties of coir fiber/poly(lactic acid) biocomposites

2019 ◽  
pp. 089270571986461
Author(s):  
Kubra Coskun ◽  
Aysenur Mutlu ◽  
Mehmet Dogan ◽  
Ebru Bozacı
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Mechanical Performance ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Coir Fiber ◽  
Test Results ◽  
Fiber Reinforced ◽  
Remarkable Effect ◽  
The Impact

The effects of enzymatic treatments on the properties of coir fiber-reinforced poly(lactic acid) (PLA) were not found in the literature. Accordingly, the effects of various enzymatic treatments on the mechanical performance of the coir fiber-reinforced PLA composites were investigated in the current study. Four different enzymes, namely lipase, lactase, pectinase, and cellulase, were used. The mechanical properties of the composites were determined by the tensile, flexural, impact tests, and dynamic mechanical analysis. According to the test results, the use of enzyme treated coir fibers affected the mechanical properties except for the flexural properties with different extents depending upon their type. The tensile strength increased with the treatments of lipase and lactase, while the treatments with pectinase and cellulase had no remarkable effect. The impact strength was improved with enzymatic treatments except for pectinase. All enzymatic treatments improved the elastic modulus below the glass transition temperature. In brief, enzymatic treatments improved the interfacial adhesion between coir fiber and PLA via the waxes and fatty acids removal and/or the increment in surface roughness.

Influence of Transesterification on the Properties of PET/MAPE Blends Prepared by Reactive Extrusion

2011 ◽  
Vol 221 ◽  
pp. 43-47 ◽  
Author(s):  
Li Gong ◽  
Qing Wen Wang ◽  
Yong Ming Song ◽  
Hai Gang Wang ◽  
Shu Juan Sui ◽  
...  
Keyword(s):  
Reactive Extrusion ◽  
Mechanical Tests ◽  
Melt Crystallization ◽  
Scanning Calorimetry ◽  
Poly Ethylene Terephthalate ◽  
Sem Micrograph ◽  
Higher Temperature ◽  
Poly Ethylene ◽  
Transesterification Catalyst ◽  
The Impact

Blends based on maleic anhydride grafted polyethylene (MAPE) and poly(ethylene terephthalate)(PET) were prepared through reactive extrusion in the presence of titanium tetrabutoxide (Ti(OBu)4) as transesterification catalyst. Mechanical properties of PET/MAPE blends(70wt./30wt.) were evaluated by mechanical tests. The Effects of Ti(OBu)4 on the structure and melt crystallization behavior of the blends were investigated by Fourier transform infrared spectroscopy(FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The addition of Ti(OBu)4 to the blends could improve the compatibility between PET and MAPE as was evidenced by the SEM micrograph in which filaments connected to a network structure was observed. With increasing the contents of Ti(OBu)4, the impact strength of the blends increased obviously, the flexural strength and tensile strength of blends did not change significantly, while the degradation of PET was gradually significant as was evidenced by FTIR analysis. Small amount of Ti(OBu)4 could hinder the crystallization of PET and make its melt peak shifted to higher temperature.

scholarly journals Pongamia Pinnata (PP) shell powder filled sisal/kevlar hybrid composites: Physico-Mechanical and Morphological Characteristics

2021 ◽  
Author(s):  
J Praveenkumara ◽  
Vidya Sagar H N ◽  
P Madhu ◽  
Yashas Gowda ◽  
Sanjay Mavinkere Rangappa ◽  
...  
Keyword(s):  
Natural Fiber ◽  
Hybrid Composites ◽  
Flexural Modulus ◽  
Morphological Characteristics ◽  
Mechanical Tests ◽  
Woven Fabrics ◽  
Pongamia Pinnata ◽  
Polymer Materials ◽  
The Impact ◽  
Shell Powder

Abstract The composite industry is attracted by natural fiber reinforced polymer materials for various valuable engineering applications due to its eco-friendly nature, less cost, enhanced mechanical properties and thermal properties. This present work aimed at incorporating sisal and kevlar woven fabrics with the epoxy matrix and to study the effect of pongamia pinnata shell powder on this sisal/ kevlar hybrid composites. The six different laminates were prepared using hand lay-up method with filler percentage varying 2 %, 4 % and 6 %. The prepared laminates cut according to ASTM standards for performing different mechanical tests. Results reveal that reduction of void percentage was observed at higher filler contents, while the incorporation of kevlar fiber enhances the impact, tensile strength and tensile modulus values. The flexural strength and inter laminar shear strength were higher for 2 % filler composites, while the highest flexural modulus, hardness values were observed for 6 % filler filled composites. The water absorption percentage was maximum for sisal laminate (L-1) and minimum for kevlar laminate L-2. The fractured tensile and flexural specimens were analyzed using scanning electron microscope (SEM).

A Study on Optical Fiber Damage Due to Optoelectronic Assembly Processes

2005 ◽  
Author(s):  
Kaustubh R. Nagarkar ◽  
Peter Borgesen ◽  
Krishnaswami Srihari
Keyword(s):  
Optical Fibers ◽  
Fiber Optic ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Sem Analysis ◽  
Primary Sources ◽  
Mechanical Degradation ◽  
Fiber Damage ◽  
The Individual ◽  
The Impact

Optoelectronic assembly processes, such as laser and photodiode packaging, connector assembly, and splicing, tend to involve extensive handling of optical fibers. These processes offer considerable likelihood of inducing severe damage to the fibers. Such damage degrades the strength of optical fibers and could result in lower than expected lifetimes in service. The objective of this research was to investigate the impact of fiber-optic assembly processes on the mechanical performance of optical fibers. Certain applications such as fiber-optic splices, connectors, and optoelectronic packages require that the protective coating of the fibers be removed through a process called ‘fiber-stripping’. The process of ‘fiber-stripping’ was characterized to identify the primary sources of mechanical degradation. The related handling and cleaning steps were also evaluated. Further, the process steps in the assembly of fiber optic connectors were closely examined and the impact of assembling fibers into adhesives was tested. Qualitative and quantitative tools have been used to investigate the problems and have been discussed in this paper. Tensile tests were used to compare the mechanical performance of the fibers. Special fixtures and test set-ups were created that enabled the testing of the fibers. Characterization techniques, such as Scanning Electron Microscopy (SEM) analysis and optical microscopy, were also used. The results have enabled to identify the contributions of the individual assembly steps that impair the strength of optical fibers. This paper provides an understanding of the potential sources and mechanisms of degradation due to such processes.

Polypropylene hybrid composites: Effect of reinforcement of sisal and carbon fibre on mechanical, thermal and morphological properties

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jyoti Agarwal ◽  
Smita Mohanty ◽  
Sanjay K Nayak
Keyword(s):  
Carbon Fibre ◽  
Mechanical Performance ◽  
Hybrid Composites ◽  
Mechanical Tests ◽  
Critical Stress Intensity Factor ◽  
Morphological Properties ◽  
Morphological Observation ◽  
Sisal Fibre ◽  
Variable Weight ◽  
The Impact

Abstract Polypropylene (PP)/sisal fibre (SF)/carbon fibre (CF) hybrid composites were prepared by melt blending process at a variable weight percentage (wt%) of carbon: sisal fibre loading (20:10, 15:15, 10:20, and 5:25). MA-g-PP (MgP) as a compatibiliser was used to improve the dispersion of the fibres within the PP matrix. The composites were subjected to mechanical tests to optimize the fibre content of CF: SF. Incorporation of 20 wt% of CF and 10 wt% of SF with 5 wt% MgP resulted in higher mechanical performance of about 67.02 and 112% over that of PP/SF composite. Similarly, the impact strength was found to be optimum which enhanced to the tune of 39.62% as compared with PP/SF composites. Halpin Tsai model was used to compare the theoretical tensile modulus of PP/SF/MgP composites and PP/SF/CF/MgP hybrid composites with experimental evaluated values. Fracture toughness parameters such as K IC (critical stress intensity factor) and G IC (critical strain energy release rate) are determined for PP/SF/MgP composites and PP/SF/CF/MgP hybrid composites and compared by using single edge notch test. DSC study showed higher melting temperature (T m ) of PP/SF/CF/MgP composites as compared to PP revealing the enhancement in thermal stability. TGA/DTG study revealed the synergistic effect of the hybrid composite thus confirming the hybridisation effect of the system. DMA study showed that the hybridisation of CF and SF within the matrix polymer contributes to an increase in the storage modulus (Eʹ). Morphological observation by SEM confirmed that the carbon fibres and sisal fibres are well uniformly dispersed within the PP matrix, in the presence of MgP.

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