scholarly journals Influence of Newly Organosolv Lignin-Based Interface Modifier on Mechanical and Thermal Properties, and Enzymatic Degradation of Polylactic Acid/Chitosan Biocomposites

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3355
Author(s):  
Faisal Amri Tanjung ◽  
Yalun Arifin ◽  
Retna Astuti Kuswardani
Keyword(s):  
Tensile Strength ◽  
Enzymatic Degradation ◽  
Enzyme Hydrolysis ◽  
Mechanical And Thermal Properties ◽  
Free Radical Copolymerization ◽  
Agent Based ◽  
Modifying Agent ◽  
Positive Effects ◽  
Organosolv Lignin ◽  
Chitosan Fiber

This article aimed to study the effects of chitosan fiber and a newly modifying agent, based on organosolv lignin, on mechanical and thermal performances and the enzymatic degradation of PLA/chitosan biocomposites. A newly modifying agent based on polyacrylic acid-grafted organosolv lignin (PAA-g-OSL) was synthesized via free radical copolymerization using t-butyl peroxide as the initiator. The biocomposites were prepared using an internal mixer and the hot-pressed method at various fiber loadings. The results demonstrate that the addition of chitosan fiber into PLA biocomposites remarkably decreases tensile strength and elongation at break. However, it improves the Young’s modulus. The modified biocomposites clearly demonstrat an improvement in tensile strength by approximately 20%, with respect to the unmodified ones, upon the presence of PAA-g-OSL. Moreover, the thermal stability of the modified biocomposites was enhanced significantly, indicating the effectiveness of the thermal protective barrier of the lignin’s aromatic structure belonging to the modifying agent during pyrolysis. In addition, a slower biodegradation rate was exhibited by the modified biocomposites, relative to the unmodified ones, that confirms the positive effects of their improved interfacial interaction, resulting in a decreased area that was degraded through enzyme hydrolysis.

Thermoplastic polyurethane/CNT nanocomposites with low electromagnetic resistance property

2021 ◽  
pp. 002199832110370
Author(s):  
Chia-Fang Lee ◽  
Chin-Wen Chen ◽  
Fu-Sheng Chuang ◽  
Syang-Peng Rwei
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermoplastic Polyurethane ◽  
Conductive Polymer ◽  
Resistance Coefficient ◽  
Equal Weight ◽  
Mechanical And Thermal Properties ◽  
Multi Wall Carbon Nanotubes ◽  
Twin Screw ◽  
Acrylic Ester

Multi-wall carbon nanotubes (MWCNTs) at 0.5 wt% to 2 wt% proportions were added to thermoplastic polyurethane (TPU) synthesized with polycarbonatediol (PCDL), 4,4’-methylene diphenyl diisocyanate (MDI), and 1,3-butanediol(1,3-BDO). To formulate a new TPU-MWCNT nanocomposite, the composite was melt-blended with a twin-screw extruder. To ensure the even dispersion of MWCNTs, dispersant (ethylene acrylic ester terpolymer; Lotader AX8900) of equal weight proportion to the added MWCNTs was also added during the blending process. Studies on the mechanical and thermal properties, and melt flow experiments and phase analysis of TPU-MWCNT nanocomposites, these nanocomposites exhibit higher tensile strength and elongation at break than neat TPU. TPU-MWCNT nanocomposites with higher MWCNT content possess higher glass-transition temperature (Tg), a lower melt index, and greater hardness. Relative to neat TPU, TPU-MWCNT nanocomposites exhibit favorable mechanical properties. By adding MWCNTs, the tensile strength of the nanocomposites increased from 7.59 MPa to 21.52 MPa, and Shore A hardness increased from 65 to 81. Additionally, TPU-MWCNT nanocomposites with MWCNTs had lower resistance coefficients; the resistance coefficient decreased from 4.97 × 1011 Ω/sq to 2.53 × 104 Ω/sq after adding MWCNTs, indicating a conductive polymer material. Finally, the internal structure of the TPU-MWCNT nanocomposites was examined under transmission electron microscopy. When 1.5 wt% or 2 wt% of MWCNTs and dispersant were added to TPU, the MWCNTs were evenly dispersed, with increased electrical conductivity and mechanical properties. The new material is applicable in the electronics industry as a conductive polymer with high stiffness.

A Study on Mechanical Properties of Short Carbon Fiber Reinforced Polycarbonate via an Injection Molding Process

2020 ◽  
Vol 18 (11) ◽  
pp. 801-805
Author(s):  
Kyung-Soo Jeon ◽  
R. Nirmala ◽  
Seong-Hwa Hong ◽  
Yong-II Chung ◽  
R. Navamathavan ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Testing Machine ◽  
Fiber Content ◽  
Injection Molding Process ◽  
Mechanical And Thermal Properties ◽  
Molding Process ◽  
Short Carbon Fiber ◽  
Short Carbon

This manuscript is dealt with the synthesis of short carbon fibers reinforced polycarbonate polymer composite by using injection modeling technique. Four different composite materials were obtained by varying the carbon fibers weight percentage of 10, 20, 30 and 40%. The synthesized carbon fibers/polycarbonate composites were characterized for their morphological, mechanical and thermal properties by means of scanning electron microscopy (SEM), universal testing machine (UTM) and IZOD strength test. The resultant carbon fibers/polycarbonate composites exhibited excellent interfacial adhesion between carbon fibers and polycarbonate resin. The tensile properties were observed to be monotonically increases with increasing carbon fiber content in the composite resin. The tensile strength of carbon fiber/polycarbonate composites with the carbon fiber content 40% were increased about 8 times than that of the pristine polycarbonate matrix. The carbon fibers/polycarbonate composites with 40 wt.% of short carbon fibers exhibited a high tensile strength and thermal conductivity. The incorporation of carbon fiber in to polycarbonate resin resulted in a significant enhancement in the mechanical and the thermal behavior. These studies suggested that the short carbon fiber incorporated polycarbonate composite matrix is a good candidate material for many technological applications.

Experimental investigation, modeling and optimization study on the mechanical properties of B4Cp/MWCNT/epoxy multi-scale hybrid composite

2020 ◽  
pp. 096739112097118
Author(s):  
Mustafa Taşyürek
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Process Parameters ◽  
Hybrid Composite ◽  
Optimization Method ◽  
High Rate ◽  
Dominant Factor ◽  
Mechanical And Thermal Properties ◽  
Multi Scale ◽  
The Matrix

In this study, process parameters and mechanical properties of the multi-scale composite were investigated experimentally and predictably. Multi-scale material includes boron carbide particles and multi walled carbon nanotubes (MWCNTs) in the epoxy-based matrix. Both reinforcements were reinforced into the matrix with various rates simultaneously. Average three tensile strength and hardness values were determined. The tensile strength and hardness were enhanced thanks to high rate of B4C usage up to 54.09% and 2.54%, respectively. The microstructure of the hybrid composite was investigated by Scanning Electron Microscopy. Also, Fourier Transform Infrared Spectroscopy was used to interpret spectral bands. The experimental data were analyzed using optimization method. Optimal process parameters for tensile strength and interfacial properties were determined. The Analysis of Variance (ANOVA) was used to obtain most significant factor and optimum levels of parameters. Finally, it was observed that B4C ratio is the most dominant factor affecting the mechanical and thermal properties.

A Combined Discrete Event, Agent - Based Approach to Modeling the Tensile Strength of One - Dimensional Fibrous Materials

2014 ◽  
Vol 9 (4) ◽  
pp. 155892501400900 ◽  
Author(s):  
Arkady Cherkassky ◽  
Eugene Bumagin
Keyword(s):  
Tensile Strength ◽  
Discrete Event ◽  
Fibrous Materials ◽  
New Approach ◽  
Agent Based ◽  
One Dimensional ◽  
Agent Based Modelling ◽  
Event Simulation ◽  
Slippage Effect ◽  
Basic Parameters

This paper presents a new approach to predict the tensile strength of one-dimensional fibrous materials. The approach combines discrete-event simulation of the fiber flow with agent-based modelling of the fiber slippage. The ability of the elaborated model of the fiber flow to track every fiber separately enables the calculation and analysis of all contacts and forces between the fibers, and the prediction of the material's tensile strength. The model is based on the phenomenon of the strength associated with the fiber slippage effect. Algorithms for modeling the cross-section and the segment tensile strength are developed. Implementation of this algorithm and the study of the behavior of the elaborated model by varying the basic parameters will be described in the Part 2 of the article.

scholarly journals Experimental investigations into mechanical and thermal properties of rapid manufactured copper parts

2019 ◽  
Vol 234 (1) ◽  
pp. 82-95 ◽  
Author(s):  
Gurminder Singh ◽  
Pulak M Pandey
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Ultimate Tensile Strength ◽  
Heating Rate ◽  
Sintering Temperature ◽  
Mechanical And Thermal Properties ◽  
Surface Porosity ◽  
Soaking Time ◽  
Ultrasonic Assisted

In the present paper, mechanical and thermal properties of rapidly manufactured copper parts were studied. The combination of three-dimensional printing and ultrasonic assisted pressureless sintering was used to fabricate copper parts. First, the ultimate tensile strength and thermal conductivity were compared between ultrasonic assisted and conventional pressureless sintered samples. The homogenously mixing of particles and local heat generation by ultrasonic vibrations promoted the sintering driving process and resulted in better mechanical and thermal properties. Furthermore, response surface methodology was adopted for the comprehensive study of the ultrasonic sintering parameters (sintering temperature, heating rate, and soaking time with ultrasonic vibrations) on ultimate tensile strength and thermal conductivity of the fabricated sample. Analysis of variance was performed to identify the significant factors and interactions. The image processing method was used to identify the surface porosity at different parameter levels to analyse the experimental results. High ultimate tensile strength was obtained at high sintering temperature, long soaking time, and slow heating rate with low surface porosity. After 60 min of soaking time, no significant effect was observed on the thermal conductivity of the fabricated sample. The significant interactions revealed less effect of soaking time at low sintering temperatures for ultimate tensile strength and less effect of heating rate at low sintering temperatures for thermal conductivity. Multi-objective optimization was carried out to identify parameters for maximum ultimate tensile strength and maximum thermal conductivity.

MECHANICAL AND THERMAL PROPERTIES OF SAWDUST CONCRETE

2017 ◽  
Vol 79 (6) ◽  
Author(s):  
Ruhal Pervez Memon ◽  
Abdul Rahman Mohd. Sam ◽  
A. S. M. Abdul Awal ◽  
Lemar Achekzai
Keyword(s):  
Heat Transfer ◽  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Lightweight Concrete ◽  
Physical And Mechanical Properties ◽  
Developing Nations ◽  
Mechanical And Thermal Properties ◽  
Construction Technology ◽  
Long Duration

 Industrialization in developing countries has resulted in an increase in agricultural output and consequent accumulation of unmanageable agro wastes. Pollution arising from such wastes is a matter of concern for many developing nations. The aim of this study is to investigate the behavior of lightweight concrete and the utilization of sawdust as waste material in concrete. This paper focuses on the manufacturing of concrete which possess long duration heat transfer by using sawdust waste. In this research, cement to sawdust ratio of 1:1, 1:2 and 1:3 by volume was prepared for sawdust concrete, and the ratio of sand was kept constant that is 1. At these ratios, the mechanical and thermal properties like density, workability, strength and heat transfer were measured after, 7, 28 and 56 days of air curing. The tests results show that with the increase in the amount of sawdust, the workability, compressive strength, tensile strength and flexural strength decreased. It also resulted in reduction of heat transfer of sawdust concrete. Taking into account the overall physical and mechanical properties, sawdust concrete can be used in construction technology. 

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.

scholarly journals Optimization and Prediction of Mechanical and Thermal Properties of Graphene/LLDPE Nanocomposites by Using Artificial Neural Networks

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
P. Noorunnisa Khanam ◽  
MA AlMaadeed ◽  
Sumaaya AlMaadeed ◽  
Suchithra Kunhoth ◽  
M. Ouederni ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Chemical Properties ◽  
Stress Transfer ◽  
Graphene Nanoplatelets ◽  
Mechanical And Thermal Properties ◽  
Degradation Temperature ◽  
The Matrix ◽  
Twin Screw ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

The focus of this work is to develop the knowledge of prediction of the physical and chemical properties of processed linear low density polyethylene (LLDPE)/graphene nanoplatelets composites. Composites made from LLDPE reinforced with 1, 2, 4, 6, 8, and 10 wt% grade C graphene nanoplatelets (C-GNP) were processed in a twin screw extruder with three different screw speeds and feeder speeds (50, 100, and 150 rpm). These applied conditions are used to optimize the following properties: thermal conductivity, crystallization temperature, degradation temperature, and tensile strength while prediction of these properties was done through artificial neural network (ANN). The three first properties increased with increase in both screw speed and C-GNP content. The tensile strength reached a maximum value at 4 wt% C-GNP and a speed of 150 rpm as this represented the optimum condition for the stress transfer through the amorphous chains of the matrix to the C-GNP. ANN can be confidently used as a tool to predict the above material properties before investing in development programs and actual manufacturing, thus significantly saving money, time, and effort.

Effect of chain extender on the mechanical and thermal resistance properties of polyurethane liners for composite propellants

Polyurethanes ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
P. Ross ◽  
G. Sevilla ◽  
J. Quagliano
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Properties ◽  
Chain Extender ◽  
Molecular Structures ◽  
Polymer Chains ◽  
Mechanical And Thermal Properties ◽  
Thermal Changes ◽  
Ft Ir ◽  
Chain Lengths

AbstractPolyurethane formulations utilized as liners for composite propellants were prepared by the reaction of toluene-2,4-diisocyanate (TDI) and isophorone diisocyanate (IPDI) with hydroxyl terminated polybutadiene (HTPB), while polymer chains were further extended with neopentyl glycol diol, NPG triol and two different triols (monoglyceryl ricinoleate, MRG and trimethylolpropane, TMP). Liners were formulated with micronized titanium dioxide mechanically dispersed in hydroxyl-terminated polybutadiene (HTPB). The molecular structures of liners were confirmed by FT-IR. Thermal properties indicated that the nature of chain extender (crosslinker) only slightly affected the temperatures for decomposition of liners. Two main thermal changes were found at 370∘C and another at around 440–500∘C, depending on the chain extender utilized. On the other side, mechanical properties varied within the range of 0,7-1,8 MPa, consistent with this kind of elastomers. Tensile strength at break was only significantly affected with TMP and MRG-chain extended liners at the lowest concentrations tested of 1,3 and 2% (w/w), respectively. However, the behaviour depended on whether TDI or IPDI isocyanate was utilized for curing. TMP 1,3% crosslinked liner cured with TDI had a tensile strength of 1,82MPa whileMRG-crosslinked liner cured with IPDI had a tensile strength of 1,56 MPa. It was observed that at the higher NCO/OH ratios essayed, tensile strength and hardness increased, improving mechanical properties. Our results confirmed that TMP and MRG triols together with NPG diols can be used to tailor mechanical and thermal properties of liners, considering their different hydroxyl functionalities and chain lengths.

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