Effect of Hydrolytic Degradation on Mechanical Properties of PCL

2016 ◽  
Vol 869 ◽  
pp. 342-345 ◽  
Author(s):  
Danyelle Campos França ◽  
Elieber Barros Bezerra ◽  
Dayanne Diniz Souza Morais ◽  
Edcleide Maria Araújo ◽  
Renate Maria Ramos Wellen
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Impact Strength ◽  
Yield Stress ◽  
Morphological Changes ◽  
Hydrolytic Degradation ◽  
Mechanical Tests ◽  
Crystalline Phases ◽  
Elongation At Break ◽  
Maximum Limit

This work investigated the effect of hydrolytic degradation on mechanical properties in tension and impact strength of poly (Ɛ-caprolactone) (PCL). PCL specimens produced by injection processing were submersed in water and exposed at 40°C into a vacuum heater. The specimens were collected from the heater after periods of 15, 30 and 45 days, respectively, followed by mechanical tests. According to the data acquired for Elastic Modulus, specimens exposed for 15 and 45 days presented a decrease of 9.65% and 13.65%; for Yield Stress a decrease of 9.08% and 10.38% was observed at same period of time compared with unexposed specimens. Concerning the Elongation at Break tests unexposed PCL reached the maximum limit of machine without fracturing while exposed specimens had their elongation at break capability decreased. Unexpected results were observed for the specimens exposed for 30 days which presented an increase of 3.43%, 3.12% and 5.88% for Elastic Modulus, Yield Stress and Strength at Break. Impact Strength presented similar trend to that of mechanical properties in tension. It is suggested that these trends are connected with morphological changes which took place in the amorphous and crystalline phases of PCL during hydrolytic degradation.

Prediction of mechanical properties of quaternary nanocomposites based on polypropylene using fuzzy logic

2020 ◽  
pp. 009524431989728
Author(s):  
Sajjad Daneshpayeh ◽  
Faramarz Ashenai Ghasemi ◽  
Shahnoosh Masoumi ◽  
Meysam Nouri Niyaraki
Keyword(s):  
Mechanical Properties ◽  
Fuzzy Logic ◽  
Elastic Modulus ◽  
Impact Strength ◽  
Considerable Increase ◽  
Graphene Nanosheets ◽  
Main Role ◽  
Elongation At Break ◽  
Prediction Of Mechanical Properties ◽  
Different Levels

The goal of the present study is to investigate and predict the mechanical properties, including impact strength, elastic modulus, and elongation-at-break of quaternary nanocomposites based on polypropylene (PP)/ethylene–propylene–diene monomer (EPDM)/glass fiber (GL)/graphene nanosheets (GPn) by fuzzy logic. Three parameters in different levels, including EPDM, GL, and GPn, were chosen for combination with a PP matrix. The fuzzy logic surfaces showed that the EPDM rubber and GPn had the main role in the elastic modulus of nanocomposites. The high levels of EPDM content resulted in a considerable increase in impact strength and, generally, the presence of EPDM had no effect on elongation-at-break.

Mechanical and Morphological Behavior of Blends Obtained from Biopolymers (PLA/PLC)

2014 ◽  
Vol 775-776 ◽  
pp. 24-28
Author(s):  
Taciana Regina de Gouveia Silva ◽  
Bartira Brandão da Cunha ◽  
Pankaj Agrawal ◽  
Edcleide Maria Araújo ◽  
Tomás Jefférson Alves de Mélo
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Elastic Modulus ◽  
Impact Strength ◽  
Polymer Blends ◽  
Poly Lactic Acid ◽  
Elongation At Break ◽  
Morphology Analysis ◽  
Morphological Behavior

In this work, the effect of the PCL content and E-GMA compatibilizer on the mechanical properties and morphology of poly (lactic acid) - PLA/ poly (ε-caprolactone)-PCL blends was investigated. The results of the mechanical properties showed that there was a reduction in the elastic modulus and tensile strength when PCL was added to PLA. The decrease in the modulus was more pronounced when the PCL content was increased from 10 to 20% (wt). The PLA/PCL/E-GMA blend showed the lower modulus and tensile strength. This blend also presented the higher elongation at break and impact strength. The morphology analysis by SEM showed that the PLA/PCL blends where characterized by lack of adhesion between the PLA and PCL phases. The presence of E-GMA in the PLA/PCL/E-GMA blend improved the adhesion between the PLA and PCL phases.Keywords: poly (latic acid); poly (ε-caprolactone); polymer blends; compatibilizer

scholarly journals Low-Temperature Mechanical Properties of High-Density and Low-Density Polyethylene and Their Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1821
Author(s):  
Ildar I. Salakhov ◽  
Nadim M. Shaidullin ◽  
Anatoly E. Chalykh ◽  
Mikhail A. Matsko ◽  
Alexey V. Shapagin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Impact Strength ◽  
Relative Elongation ◽  
High Density ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Elongation At Break ◽  
Subzero Temperatures ◽  
Izod Impact

Low-temperature properties of high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and their blends were studied. The analyzed low-temperature mechanical properties involve the deformation resistance and impact strength characteristics. HDPE is a bimodal ethylene/1-hexene copolymer; LDPE is a branched ethylene homopolymer containing short-chain branches of different length; LLDPE is a binary ethylene/1-butene copolymer and an ethylene/1-butene/1-hexene terpolymer. The samples of copolymers and their blends were studied by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), 13С NMR spectroscopy, and dynamic mechanical analysis (DMA) using testing machines equipped with a cryochamber. It is proposed that such parameters as “relative elongation at break at −45 °C” and “Izod impact strength at −40 °C” are used instead of the ductile-to-brittle transition temperature to assess frost resistance properties because these parameters are more sensitive to deformation and impact at subzero temperatures for HDPE. LLDPE is shown to exhibit higher relative elongation at break at −45 °C and Izod impact strength at −20 ÷ 60 °C compared to those of LDPE. LLDPE terpolymer added to HDPE (at a content ≥ 25 wt.%) simultaneously increases flow properties and improves tensile properties of the blend at −45 °C. Changes in low-temperature properties as a function of molecular weight, MWD, crystallinity, and branch content were determined for HDPE, LLDPE, and their blends. The DMA data prove the resulting dependences. The reported findings allow one to understand and predict mechanical properties in the HDPE–LLDPE systems at subzero temperatures.

scholarly journals The Structure and Mechanical Properties of Hemp Fibers-Reinforced Poly(ε-Caprolactone) Composites Modified by Electron Beam Irradiation

2021 ◽  
Vol 11 (12) ◽  
pp. 5317
Author(s):  
Rafał Malinowski ◽  
Aneta Raszkowska-Kaczor ◽  
Krzysztof Moraczewski ◽  
Wojciech Głuszewski ◽  
Volodymyr Krasinskyi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Beam ◽  
Impact Strength ◽  
Flexural Modulus ◽  
Natural Fibers ◽  
High Energy ◽  
Electron Radiation ◽  
Elongation At Break ◽  
Hemp Fibers

The need for the development of new biodegradable materials and modification of the properties the current ones possess has essentially increased in recent years. The aim of this study was the comparison of changes occurring in poly(ε-caprolactone) (PCL) due to its modification by high-energy electron beam derived from a linear electron accelerator, as well as the addition of natural fibers in the form of cut hemp fibers. Changes to the fibers structure in the obtained composites and the geometrical surface structure of sample fractures with the use of scanning electron microscopy were investigated. Moreover, the mechanical properties were examined, including tensile strength, elongation at break, flexural modulus and impact strength of the modified PCL. It was found that PCL, modified with hemp fibers and/or electron radiation, exhibited enhanced flexural modulus but the elongation at break and impact strength decreased. Depending on the electron radiation dose and the hemp fibers content, tensile strength decreased or increased. It was also found that hemp fibers caused greater changes to the mechanical properties of PCL than electron radiation. The prepared composites exhibited uniform distribution of the dispersed phase in the polymer matrix and adequate adhesion at the interface between the two components.

scholarly journals Effect of Moisture Content on the Processing and Mechanical Properties of a Biodegradable Polyester

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1616
Author(s):  
Vincenzo Titone ◽  
Antonio Correnti ◽  
Francesco Paolo La Mantia
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Moisture Content ◽  
Mechanical Testing ◽  
Hydrolytic Degradation ◽  
Slight Reduction ◽  
Biodegradable Polyester ◽  
Molding Process ◽  
Elongation At Break ◽  
Effect Of Moisture

This work is focused on the influence of moisture content on the processing and mechanical properties of a biodegradable polyester used for applications in injection molding. The pellets of the biodegradable polyester were exposed under different relative humidity conditions at a constant temperature before being compression molded. The compression-molded specimens were again placed under the above conditions before the mechanical testing. With all these samples, it is possible to determine the effect of moisture content on the processing and mechanical properties separately, as well as the combined effect of moisture content on the mechanical properties. The results obtained showed that the amount of absorbed water—both before processing and before mechanical testing—causes an increase in elongation at break and a slight reduction of the elastic modulus and tensile strength. These changes have been associated with possible hydrolytic degradation during the compression molding process and, in particular, with the plasticizing action of the moisture absorbed by the specimens.

Graphite/Bio-Based Epoxy Composites: The Mechanical Properties Interface

2015 ◽  
Vol 799-800 ◽  
pp. 115-119 ◽  
Author(s):  
Anika Zafiah M. Rus ◽  
Nur Munirah Abdullah ◽  
M.F.L. Abdullah ◽  
M. Izzul Faiz Idris
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Filler Content ◽  
Weight Percent ◽  
Epoxy Composites ◽  
Elongation At Break ◽  
Graphite Content ◽  
Dispersion Condition ◽  
Strong Interfacial Bonding

Graphite reinforced bio-based epoxy composites with different particulate fractions of graphite were investigated for mechanical properties such as tensile strength, elastic modulus and elongation at break. The graphite content was varied from 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.% by weight percent in the composites. The results showed that the mechanical properties of the composites mainly depend on dispersion condition of the treated graphite filler, aggregate structure and strong interfacial bonding between treated graphite in the bio-based epoxy matrix. The composites showed improved tensile strength and elastic modulus with increase treated graphite weight loading. This also revealed the composites with increasing filler content was decreasing the elongation at break.

Effect of Wood Filler Concentration on Physical and Mechanical Properties of PLA-Based Composites

2021 ◽  
Vol 887 ◽  
pp. 110-115
Author(s):  
G.A. Sabirova ◽  
R.R. Safin ◽  
N.R. Galyavetdinov
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Composite Materials ◽  
Impact Strength ◽  
Wood Flour ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Filler Concentration ◽  
High Concentration

This paper presents the findings of experimental studies of the physical and mechanical properties of wood-filled composites based on polylactide (PLA) and vegetable filler in the form of wood flour (WF) thermally modified at 200-240 °C. It also reveals the dependence of the tensile strength, impact strength, bending elastic modulus, and density of composites on the amount of wood filler and the temperature of its thermal pre-modification. We established that an increase in the concentration of the introduced filler and the degree of its heat treatment results in a decrease of the tensile strength, impact strength and density of composite materials, while with a lower binder content, thermal modification at 200 °C has a positive effect on bending elastic modulus. We also found that 40 % content of a wood filler heated to 200 °C is sufficient to maintain relatively high physical and mechanical properties of composite materials. With a higher content of a wood filler, the cost can be reduced but the quality of products made of this material may significantly deteriorate. However, depending on the application and the life cycle of this product, it is possible to develop a formulation that includes a high concentration of filler.

Development of Banana/Coir Natural Fibers Reinforced Polypropylene Hybrid Composites: The Effect of MA-g-PP (Maleic Anhydride Grafted Polypropylene) on Mechanical Properties and Thermal Properties

2021 ◽  
Vol 32 ◽  
pp. 85-97
Author(s):  
Gunturu Bujjibabu ◽  
Vemulapalli Chittaranjan Das ◽  
Malkapuram Ramakrishna ◽  
Konduru Nagarjuna
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Coupling Agent ◽  
Mechanical Performance ◽  
Hybrid Composites ◽  
Natural Fibers ◽  
Mechanical Tests ◽  
Coir Fiber ◽  
Banana Fiber ◽  
C Fibers

Banana/Coir fiber reinforced polypropylene hybrid composites was formulated by using twin screw extruder and injection molding machine. Specimens were prepared untreated and treated B/C Hybrid composites with 4% and 8% of MA-g-PP to increase its compatibility with the polypropylene matrix. Both the without MA-g-PP and with MA-g-PP B/C hybrid composites was utilized and three levels of B/C fiber loadings 15/5, 10/10 and 5/15 % were used during manufacturing of B/C reinforced polypropylene hybrid composites. In this work mechanical performance (tensile, flexural and impact strengths) of untreated and treated (coupling agent) with 4% and 8% of MA-g-PP B/C fibers reinforced polypropylene hybrid composite have been investigated. Treated with MA-g-PP B/C fibers reinforced specimens explored better mechanical properties compared to untreated B/C fibers reinforced polypropylene hybrid composites. Mechanical tests represents that tensile, flexural and impact strength increases with increase in concentration of coupling agent compared to without coupling agent MA-g-PP hybrid composites . B/C fibers reinforced polymer composites exhibited higher tensile, flexural and impact strength at 5% of Banana fiber, 15% of fiber Coir in the presence of 8% of MA-g-PP compared to 4% of MA-g-PP and untreated hybrid composites. The percentage of water absorption in the B/C fibers reinforced polypropylene hybrid composites resisted due to the presence of coupling agent MA-g-PP and thermogravimetry analysis (TGA) also has done.

scholarly journals Effect of Gamma Radiation on the Mechanical Properties of Natural Fabric Reinforced Polyester Composites

2019 ◽  
Vol 27 (4(136)) ◽  
pp. 88-93
Author(s):  
K.Z.M. Abdul Motaleb ◽  
Md Shariful Islam ◽  
Rimvydas Milašius
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Gamma Radiation ◽  
Bending Strength ◽  
Polyester Resin ◽  
Radiation Doses ◽  
Elongation At Break ◽  
Bending Modulus ◽  
Polyester Composites

Two types of composites:(1) pineapple fabric reinforced polyester resin (Pineapple/PR) and (2) jute fabric reinforced polyester resin (Jute/PR) were prepared and the mechanical properties investigated for various gamma radiation doses ranging from 100-500 krad. Properties like tensile strength, Young’s modulus, elongation-at-break, bending strength, bending modulus and impact strength were increased significantly by 19%, 32%, 45%, 32%, 47% and 20%, respectively, at a dose of 300 krad for Pineapple/PR, and by 47%, 49%, 42%, 45%, 52% and 65%, respectively, at a dose of 200 krad for the Jute/PR composite in comparison to the non-irradiated composite. Gamma radiation improved the mechanical properties, but overdoses of radiation even caused a reduction in them.

Biomimetic composites inspired by venous leaf

2017 ◽  
Vol 52 (3) ◽  
pp. 361-372 ◽  
Author(s):  
Gongdai Liu ◽  
R Ghosh ◽  
A Vaziri ◽  
A Hossieni ◽  
D Mousanezhad ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Yield Stress ◽  
Poisson’S Ratio ◽  
Composite Structures ◽  
Volume Fraction ◽  
Matrix Material ◽  
Poisson's Ratio ◽  
Fiber Volume ◽  
Young’S Moduli

A typical plant leaf can be idealized as a composite having three principal fibers: the central mid-fiber corresponding to the mid-rib, straight parallel secondary fibers attached to the mid-fiber representing the secondary veins, and then another set of parallel fibers emanating from the secondary fibers mimicking the tertiary fibers embedded in a matrix material. This paper introduces a biomimetic composite design inspired by the morphology of venous leafs and investigates the effects of venation morphologies on the in-plane mechanical properties of the biomimetic composites using finite element method. The mechanical properties such as Young’s moduli, Poisson’s ratio, and yield stress under uniaxial loading of the resultant composite structures was studied and the effect of different fiber architectures on these properties was investigated. To this end, two broad types of architectures were used both having similar central main fiber but differing in either having only secondary fibers or additional tertiary fibers. The fiber and matrix volume fractions were kept constant and a comparative parametric study was carried out by varying the inclination of the secondary fibers. The results show that the elastic modulus of composite in the direction of main fiber increases linearly with increasing the angle of the secondary fibers. Furthermore, the elastic modulus is enhanced if the secondary fibers are closed, which mimics composites with closed cellular fibers. In contrast, the elastic modulus of composites normal to the main fiber ( x direction) exponentially decreases with the increase of the angle of the secondary fibers and it is little affected by having secondary fibers closed. Similar results were obtained for the yield stress of the composites. The results also indicate that Poisson’s ratio linearly increases with the secondary fiber angle. The results also show that for a constant fiber volume fraction, addition of various tertiary fibers may not significantly enhance the mechanical properties of the composites. The mechanical properties of the composites are mainly dominated by the secondary fibers. Finally, a simple model was proposed to predict these behaviors.

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