scholarly journals Carbon Fiber Composites of Pure Polypropylene and Maleated Polypropylene Blends Obtained from Injection and Compression Moulding

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
D. Pérez-Rocha ◽  
A. B. Morales-Cepeda ◽  
F. Navarro-Pardo ◽  
T. Lozano-Ramírez ◽  
P. G. LaFleur
Keyword(s):  
Mechanical Performance ◽  
Impact Resistance ◽  
Structural Features ◽  
Strength Properties ◽  
Favourable Effect ◽  
Carbon Fiber Composites ◽  
Compression Moulding ◽  
Scanning Calorimetry ◽  
Noticeable Effect ◽  
Maleated Polypropylene

A comparative study of the mechanical performance of PP and PP/PP-g-MAH blends reinforced with carbon fibre (CF) obtained by two different moulding techniques is presented. Three filler contents were used for fabricating the composites: 1, 3, and 5 pph (parts per hundred). The crystallisation behaviour of the composites was studied by differential scanning calorimetry. Morphological and structural features of these samples were observed by atomic field microscopy and Fourier-transform infrared spectroscopy, respectively. Mechanical properties of the injection and compression moulded composites were evaluated by means of tensile and impact resistance tests. The fracture surface of the impacted samples was observed by scanning electron microscopy. The processing method had a noticeable effect on the results obtained in these tests. Young’s modulus was enhanced up to 147% when adding 5 pph CF to a PP matrix when processed by compression moulding. Addition of PP-g-MAH and CF had a favourable effect on the tensile and impact strength properties in most samples; these composites showed improved performance as the filler content was increased.

Comparison and characterization of discontinuous carbon fiber liquid-molded nylon to hydroentanglement/compression-molded composites

2019 ◽  
Vol 33 (8) ◽  
pp. 1078-1093 ◽  
Author(s):  
Siddhartha Brahma ◽  
Selvum Pillay ◽  
Haibin Ning
Keyword(s):  
Carbon Fiber ◽  
Mechanical Performance ◽  
Weight Fraction ◽  
Polyamide 6 ◽  
Compression Molding ◽  
Fiber Composites ◽  
Strength Properties ◽  
Processing Temperature ◽  
Carbon Fiber Composites ◽  
Scanning Calorimetry

This article looks at liquid molding of polyamide 6 (PA6) via vacuum assisted resin transfer molding (VARTM) of discontinuous recycled carbon fiber composites. Its mechanical, thermal, and optical characterization is compared to hydroentanglement/compression molding. Liquid-molded composites show consistent improvement in their tensile and impact properties at three different weight fractions in comparison to hydroentanglement/compression molding. There was roughly a 10 and 13% increase in its tensile strength, modulus, and impact strength properties at 30 and 40% weight fractions and almost a 120% increase at 50% weight fraction. Fourier-transform infrared spectroscopy and differential scanning calorimetry data show that the caprolactam was synthesized to PA6 and was comparable to commercial grade PA6 used in this research. Scanning electron microscopy studies show poor wet out in the case of hydroentanglement/compression molding as compared to VARTM. The combination of better mechanical performance and lower processing temperature (165°C) shows promise in being a viable method to process PA6-based recycled fiber composites.

On the Development and Characterization of Rheological and Mechanical Properties of Polylactide Blends with Polybutylene Adipate Terephthalate

2020 ◽  
Vol 850 ◽  
pp. 118-123
Author(s):  
Arturs Eriks Nesaule ◽  
Elina Didrihsone ◽  
Remo Merijs-Meri ◽  
Oskars Grigs ◽  
Jānis Zicāns
Keyword(s):  
Polymer Blend ◽  
High Performance ◽  
Impact Resistance ◽  
Structural Features ◽  
Scanning Calorimetry ◽  
Multi Stage ◽  
Research Cycle ◽  
Twin Screw ◽  
First Results

Within the current report the first results of the upcoming multi-stage research cycle on the development of high-performance environmentally friendly PLA/PBAT blend based composite materials are presented. Development and basic characterization of PLA/PBAT blends at various wt.-to-wt. ratios of the base polymeric components is performed. Rheological properties of PLA and PBAT have been investigated by means of rotational viscometry to define the optimal blending parameters. PLA/PBAT blends have been obtained by using twin-screw extrusion. Structural features of the obtained polymer blend compositions have been revealed by means of Fourier transform infrared spectroscopy. Crystallization behavior of the obtained polymer blend compositions have been characterized by means of differential scanning calorimetry. Thermal stability of the obtained polymer blend compositions has been studied by using thermogravimetric analysis. Mechanical behavior of the obtained polymer blend compositions has been studied by means of both quasistatic (in respects to tensile and flexural properties) and dynamic tests (impact resistance).

scholarly journals On the Use of Paper Sludge as Filler in Biocomposites for Injection Moulding

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2688
Author(s):  
Vito Gigante ◽  
Patrizia Cinelli ◽  
Marco Sandroni ◽  
Roberto D’ambrosio ◽  
Andrea Lazzeri ◽  
...  
Keyword(s):  
Injection Moulding ◽  
Mechanical Performance ◽  
Impact Resistance ◽  
Mechanical Tests ◽  
Lepidium Sativum ◽  
Poly Lactic Acid ◽  
Paper Sludge ◽  
Scanning Calorimetry ◽  
Twin Screw ◽  
Acetyl Tributyl Citrate

The potential use of paper sludge (PS) as filler in the production of bio-composites based on poly lactic acid (PLA) and polybutylene adipate terephthalate (PBAT) was investigated. PS/PLA/PBAT composites, with addition of acetyl tributyl citrate (ATBC) as biobased plasticizer, were produced with PS loadings up to 30 wt.% by twin-screw extrusion followed by injection moulding. The composites were characterized by rheological measurements, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and mechanical tests (tensile and impact resistance) to study the effect of PS on the processability, thermal stability, crystallinity and mechanical performance of polymeric matrix. The optimized composites at higher PS content were successfully processed to produce pots for horticulture and, in view of this application, preliminary phytotoxicity tests were conducted using the germination test on Lepidium sativum L. seeds. Results revealed that developed composites up to 30 wt.% PS had good processability by extrusion and injection moulding showing that PS is a potential substitute of calcium carbonate as filler in the production of bio-composites, and the absence of phytotoxic effects showed the possibility of their use in the production of pots/items for applications in floriculture and/or horticulture.

Mechanical characterisation and modelling of randomly oriented strand architecture and their hybrids – A general review

2018 ◽  
Vol 37 (8) ◽  
pp. 548-580 ◽  
Author(s):  
Swaroop B Visweswaraiah ◽  
Marina Selezneva ◽  
Larry Lessard ◽  
Pascal Hubert
Keyword(s):  
Composite Structures ◽  
Mechanical Performance ◽  
Synergistic Effects ◽  
Measurement Techniques ◽  
Research Work ◽  
Strength Properties ◽  
Material System ◽  
Compression Moulding ◽  
Mechanical Characterisation ◽  
And Performance

A comprehensive review of the mechanical characterisation and modelling of randomly oriented strand material architecture and their hybrids with laminates is presented. Randomly oriented strand composites are long discontinuous fibre systems that exhibit excellent formability characteristics and stiffness properties comparable to quasi-isotropic laminates, allowing their use in the manufacture of intricate geometric parts for automotive and aerospace industries. Randomly oriented strand architecture complements out-of-autoclave methods such as compression moulding, thermostamping and resin-transfer moulding leading to cost-reduction. Their applicability is limited to non-structural and low-load bearing applications due to their low strength properties. Continuous fibre aerospace preforms exhibiting excellent mechanical performance possess low formability characteristics and are confined to simple shell-like geometries with minimal curvatures, while incurring high-costs and long manufacturing times. Hybridisation of randomly oriented strand and with other material architectures represents trade-off solutions of formability and performance characteristics often yielding synergistic effects. Seemingly simple, randomly oriented strand architecture is a complex material system that poses several structural and process challenges. This work categorises the pertinent research work from the literature on the mechanical characterisation into the framework of a formal characterisation environment of composite structures that includes the coupon, the part and structural levels. The manufacturing, dispersion methods and measurement techniques are qualitatively assessed with reference to the mechanical properties. The discussion on modelling involves the identification of crucial characteristics of significant analytical and numerical modelling techniques devised for the prediction of the mechanical behaviour of randomly oriented strand composites and their hybrids. Emphasis is on the methods of stiffness and strength prediction. Our perspectives on the effective use of randomly oriented strand composites and their hybrids are discussed. Process characterisation and process modelling of randomly oriented strand composites and their hybrids are beyond the scope of this article.

pH-Dependent Thermal Stability of Vibrio cholerae L-asparaginase

2019 ◽  
Vol 26 (10) ◽  
pp. 743-750 ◽  
Author(s):  
Remya Radha ◽  
Sathyanarayana N. Gummadi
Keyword(s):  
Vibrio Cholerae ◽  
Conformational Changes ◽  
Kinetic Studies ◽  
Structural Features ◽  
Structure Stability ◽  
Kcal Mole ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
Ph Dependent ◽  
Ph Range

Background:pH is one of the decisive macromolecular properties of proteins that significantly affects enzyme structure, stability and reaction rate. Change in pH may protonate or deprotonate the side group of aminoacid residues in the protein, thereby resulting in changes in chemical and structural features. Hence studies on the kinetics of enzyme deactivation by pH are important for assessing the bio-functionality of industrial enzymes. L-asparaginase is one such important enzyme that has potent applications in cancer therapy and food industry.Objective:The objective of the study is to understand and analyze the influence of pH on deactivation and stability of Vibrio cholerae L-asparaginase.Methods:Kinetic studies were conducted to analyze the effect of pH on stability and deactivation of Vibrio cholerae L-asparaginase. Circular Dichroism (CD) and Differential Scanning Calorimetry (DSC) studies have been carried out to understand the pH-dependent conformational changes in the secondary structure of V. cholerae L-asparaginase.Results:The enzyme was found to be least stable at extreme acidic conditions (pH< 4.5) and exhibited a gradual increase in melting temperature from 40 to 81 °C within pH range of 4.0 to 7.0. Thermodynamic properties of protein were estimated and at pH 7.0 the protein exhibited ΔG37of 26.31 kcal mole-1, ΔH of 204.27 kcal mole-1 and ΔS of 574.06 cal mole-1 K-1.Conclusion:The stability and thermodynamic analysis revealed that V. cholerae L-asparaginase was highly stable over a wide range of pH, with the highest stability in the pH range of 5.0–7.0.

scholarly journals Wastes from Agricultural Silage Film Recycling Line as a Potential Polymer Materials

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1383
Author(s):  
Jerzy Korol ◽  
Aleksander Hejna ◽  
Klaudiusz Wypiór ◽  
Krzysztof Mijalski ◽  
Ewelina Chmielnicka
Keyword(s):  
Vinyl Acetate ◽  
Thermal Performance ◽  
Mechanical Performance ◽  
Ethylene Vinyl Acetate ◽  
Tensile Tests ◽  
Solid Particles ◽  
Polymer Materials ◽  
Slight Reduction ◽  
Scanning Calorimetry ◽  
Crystallinity Degree

The recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for potential methods for their utilization. In the presented work, we investigated the recycling potential of wastes originated from the agricultural films recycling line. Their structure and properties were analyzed, and they were modified with 2.5 wt % of commercially available compatibilizers. The mechanical and thermal performance of modified wastes were evaluated by tensile tests, thermogravimetric analysis, and differential scanning calorimetry. It was found that incorporation of such a small amount of modifiers may overcome the drawbacks caused by the presence of impurities. The incorporation of maleic anhydride-grafted compounds enhanced the tensile strength of wastes by 13–25%. The use of more ductile compatibilizers—ethylene-vinyl acetate and paraffin increased the elongation at break by 55–64%. The presence of compatibilizers also reduced the stiffness of materials resulting from the presence of solid particles. It was particularly emphasized for styrene-ethylene-butadiene-styrene and ethylene-vinyl acetate copolymers, which caused up to a 20% drop of Young’s modulus. Such effects may facilitate the further applications of analyzed wastes, e.g., in polymer film production. Thermal performance was only slightly affected by compatibilization. It caused a slight reduction in polyethylene melting temperatures (up to 2.8 °C) and crystallinity degree (up to 16%). For more contaminated materials, the addition of compatibilizers caused a minor reduction in the decomposition onset (up to 6 °C). At the same time, for the waste after three washing cycles, thermal stability was improved. Moreover, depending on the desired properties and application, materials do not have to go through the whole recycling line, simplifying the process, reducing energy and water consumption. The presented results indicate that it is possible to efficiently use the materials, which do not have to undergo the whole recycling process. Despite the presence of impurities, they could be applied in the manufacturing of products which do not require exceptional mechanical performance.

scholarly journals Is Micro X-ray Computer Tomography a Suitable Non-Destructive Method for the Characterisation of Dental Materials?

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1271
Author(s):  
Andreas Koenig ◽  
Leonie Schmohl ◽  
Johannes Scheffler ◽  
Florian Fuchs ◽  
Michaela Schulz-Siegmund ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Computer Tomography ◽  
Mechanical Performance ◽  
Dental Materials ◽  
Three Dimensional ◽  
X Rays ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Multiple Measurements ◽  
High Doses

The aim of the study was to investigate the effect of X-rays used in micro X-ray computer tomography (µXCT) on the mechanical performance and microstructure of a variety of dental materials. Standardised bending beams (2 × 2 × 25 mm3) were forwarded to irradiation with an industrial tomograph. Using three-dimensional datasets, the porosity of the materials was quantified and flexural strength was investigated prior to and after irradiation. The thermal properties of irradiated and unirradiated materials were analysed and compared by means of differential scanning calorimetry (DSC). Single µXCT measurements led to a significant decrease in flexural strength of polycarbonate with acrylnitril-butadien-styrol (PC-ABS). No significant influence in flexural strength was identified for resin-based composites (RBCs), poly(methyl methacrylate) (PMMA), and zinc phosphate cement (HAR) after a single irradiation by measurement. However, DSC results suggest that changes in the microstructure of PMMA are possible with increasing radiation doses (multiple measurements, longer measurements, higher output power from the X-ray tube). In summary, it must be assumed that X-ray radiation during µXCT measurement at high doses can lead to changes in the structure and properties of certain polymers.

Effect of toughened polyamide-coated carbon fiber fabric on the mechanical performance and fracture toughness of CFRP

2021 ◽  
pp. 002199832199945
Author(s):  
Jong H Eun ◽  
Bo K Choi ◽  
Sun M Sung ◽  
Min S Kim ◽  
Joon S Lee
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Photoelectron Spectroscopy ◽  
Mechanical Performance ◽  
Epoxy Composites ◽  
Scanning Calorimetry ◽  
Internal Damage ◽  
Impact Tests ◽  
Flexural Tests ◽  
The Impact

In this study, carbon/epoxy composites were manufactured by coating with a polyamide at different weight percentages (5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%) to improve their impact resistance and fracture toughness. The chemical reaction between the polyamide and epoxy resin were examined by fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray photoelectron spectroscopy. The mechanical properties and fracture toughness of the carbon/epoxy composites were analyzed. The mechanical properties of the carbon/epoxy composites, such as transverse flexural tests, longitudinal flexural tests, and impact tests, were investigated. After the impact tests, an ultrasonic C-scan was performed to reveal the internal damage area. The interlaminar fracture toughness of the carbon/epoxy composites was measured using a mode I test. The critical energy release rates were increased by 77% compared to the virgin carbon/epoxy composites. The surface morphology of the fractured surface was observed. The toughening mechanism of the carbon/epoxy composites was suggested based on the confirmed experimental data.

Inosose-Flüssigkristalle / Inosose Liquid Crystals

1990 ◽  
Vol 45 (7) ◽  
pp. 1084-1090 ◽  
Author(s):  
Klaus Praefcke ◽  
Bernd Kohne ◽  
Andreas Eckert ◽  
Joachim Hempel
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
High Temperature ◽  
Liquid Crystalline ◽  
Structural Features ◽  
Lyotropic Liquid Crystal ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Alkyl Chains

Six S,S-dialkyl acetals 2a-f of inosose (1), tripodal in structure, have been synthesized, characterized and investigated by optical microscopy and differential scanning calorimetry (d.s.c.). The four S,S-acetals 2c-f with sufficiently long alkyl chains are thermotropic liquid crystalline; 2 e and 2 f are even dithermomesomorphic. Each of these four inosose derivatives 2c-f exhibits monotropically a most likely cubic mesophase (MI); in addition 2e and 2f show enantiotropically a hexagonal mesophase (Hx) with a non-covalent, supramolecular H-bridge architecture. Whereas the nature of the optically isotropic mesophase MI needs further clarification the stable high temperature mesophase Hx of 2 e and 2 f has been established by a miscibility test using a sugar S,S-dialkyl acetal also tripodal in structure and with a Hx phase proved by X-ray diffraction, but in contrast to 2 with an acyclic hydrophilic part. Similarities of structural features between the Hx-phases of 2e and 2f as well as of other thermotropic and lyotropic liquid crystal systems are discussed briefly.

Optimization of Curing Conditions and Nanofiller Incorporation for Production of High Performance Laminated Kevlar/Epoxy Nanocomposites

2018 ◽  
Author(s):  
Abdel-Hamid I. Mourad ◽  
Mouza S. Al Mansoori ◽  
Lamia A. Al Marzooqi ◽  
Farah A. Genena ◽  
Nizamudeen Cherupurakal
Keyword(s):  
Oil And Gas ◽  
Mechanical Performance ◽  
Thermo Gravimetric Analysis ◽  
Applied Pressure ◽  
Curing Temperature ◽  
Gravimetric Analysis ◽  
Epoxy Nanocomposites ◽  
Scanning Calorimetry ◽  
Curing Conditions ◽  
Weight Percentage

Kevlar composite materials are getting scientific interest in repairing of oil and gas pipelines in both offshore and onshore due to their unique properties. Curing is one of the major factor in deciding the final mechanical performance of laminated Kevlar/epoxy nanocomposites. The parameters such as curing time, temperature and applied pressure during the hot pressing will affect chemistry of crosslinking of the epoxy matrix and interaction of epoxy with the Kevlar fiber. The present study is carried out to evaluate the optimal curing conditions of the Kevlar/epoxy nanocomposites. Three different nanofillers (namely Multi walled Carbon nanotubes (MWCNT), Silicon Carbide (SiC) and Aluminum Oxide (Al2O3)) are incorporated in different weight percentage. Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analysis (TGA) tests are carried out to determine the thermal stability and optimal curing conditions. Mechanical performance is investigated by conducting flexure, and drop weight tests. The results show that, the optimal curing temperature for maximizing the mechanical properties is at 170°C. Peeling off the Kevlar layers are observed for nanocomposite samples cured under 100°C. Mechanical strength of the composites is enhanced by optimizing the curing conditions and nanofiller contents.

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