Aging and Fracture Behavior of Polymers

1991 ◽  
Vol 226 ◽  
Author(s):  
A. Chudnovsky ◽  
C.P. Bosnyak
Keyword(s):  
Continuum Mechanics ◽  
Environmental Effects ◽  
Service Time ◽  
Fracture Behavior ◽  
Mechanical Performance ◽  
Mechanical Stresses ◽  
Polymer Materials ◽  
Design Criteria ◽  
Morphological Transformation ◽  
New Approach

AbstractSignificant changes in polymer materials and their subsequent mechanical performance can occur within an expected engineering service time. These changes can be further exacerbated with environmental effects such as with solvents and mechanical stresses. Examples are given of premature field failures which illustrate the inadequacy of existing understanding and design criteria. A new approach is outlined which is based on the coupling of two fundamental concepts; a geometrical representation of material morphology on various scales and thermodynamics of morphological transformation. These concepts allow one to bridge an existing understanding of aging on molecular and morphological levels with a phenomenological continuum mechanics approach.

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 The Influence of Manufacturing Parameters on the Mechanical Behaviour of PLA and ABS Pieces Manufactured by FDM: A Comparative Analysis

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1333 ◽  
Author(s):  
Adrián Rodríguez-Panes ◽  
Juan Claver ◽  
Ana Camacho
Keyword(s):  
Tensile Strength ◽  
Mechanical Behaviour ◽  
Mechanical Performance ◽  
Acrylonitrile Butadiene Styrene ◽  
Polymer Materials ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Layer Orientation ◽  
Lower Variability

This paper presents a comparative study of the tensile mechanical behaviour of pieces produced using the Fused Deposition Modelling (FDM) additive manufacturing technique with respect to the two types of thermoplastic material most widely used in this technique: polylactide (PLA) and acrylonitrile butadiene styrene (ABS). The aim of this study is to compare the effect of layer height, infill density, and layer orientation on the mechanical performance of PLA and ABS test specimens. The variables under study here are tensile yield stress, tensile strength, nominal strain at break, and modulus of elasticity. The results obtained with ABS show a lower variability than those obtained with PLA. In general, the infill percentage is the manufacturing parameter of greatest influence on the results, although the effect is more noticeable in PLA than in ABS. The test specimens manufactured using PLA perform more rigidly and they are found to have greater tensile strength than ABS. The bond between layers in PLA turns out to be extremely strong and is, therefore, highly suitable for use in additive technologies. The methodology proposed is a reference of interest in studies involving the determination of mechanical properties of polymer materials manufactured using these technologies.

Estimation of Service Life of Mechanical Engineering Components

2019 ◽  
Vol 799 ◽  
pp. 71-76
Author(s):  
Oskars Linins ◽  
Ernests Jansons ◽  
Armands Leitans ◽  
Irina Boiko ◽  
Janis Lungevics
Keyword(s):  
Service Life ◽  
Service Time ◽  
Surface Texture ◽  
Mechanical Engineering ◽  
Friction Pair ◽  
Theory Of Elasticity ◽  
New Approach ◽  
Material Fatigue ◽  
Texture Parameters ◽  
3D Surface Texture

The paper is aimed to the methodology for estimation of service life of mechanical engineering components in the case of elastic-plastic contact of surfaces. Well-known calculation methods depending on physics, theory of probability, the analysis of friction pair’ shape and fit include a number of parameters that are difficult or even impossible to be technologically controlled in the manufacturing of mechanical engineering components. The new approach for wear rate estimation using surface texture parameters as well as physical-mechanical properties and geometric parameters of components is proposed. The theoretical part of the calculations is based on the 3D surface texture principles, the basics of material fatigue theory, the theory of elasticity and the contact mechanics of surfaces. It is possible to calculate the service time of the machine, but the process of running-in of the components is relatively short (less than 5%), therefore, the service time is mainly determined by a normal operating period, which also was used to evaluate this period. The calculated input parameters are technologically and metrologically available and new method for calculating the service time can be used in the design process of the equipment. The results of approbation of the method for estimation service time of mechanical engineering, which prove the applicability of mentioned method, are offered as well.

Laser direct writing of nanocompounds

2011 ◽  
Vol 1365 ◽  
Author(s):  
Andreas Ostendorf ◽  
M’Barek Chakif ◽  
Qingchuan Guo
Keyword(s):  
Polymer Materials ◽  
Polymerization Process ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Bioactive Materials ◽  
New Approach ◽  
Photosensitive Polymer ◽  
The Matrix ◽  
Inorganic Nanomaterials ◽  
Huge Variety

ABSTRACTLaser direct polymerization has been proven as a powerful tool to generate microstructures. Often photosensitive polymer materials are used because they can be tuned by photoactive molecules to be susceptible to a specific wavelength of light to initiate the polymerization process. One of the main drawbacks of this technique is the lack of functional polymers, e.g. conductive, magnetic, mechanical, optical or bioactive materials. Nanocomposites (nanocompounds), i.e. polymers with inorganic nanomaterials incorporated in the matrix offer a huge variety of new functionalities. A new approach will be presented how functional nanocomposite polymers can be generated and used for laser direct writing techniques. This can open the door for completely new MEMS and MOEMS devices comprising active and passive subcomponents.

Radiotechnical Signal Processing Techniques for Polymer Materials Structure Analysis

2017 ◽  
Vol 381 ◽  
pp. 59-63 ◽  
Author(s):  
Vladimir Klimentievitch Kachanov ◽  
Igor Vacheslavovitch Sokolov ◽  
Serguei Vladimirovitch Lebedev ◽  
Vladimir Vladimirovitch Pervushin
Keyword(s):  
Structure Analysis ◽  
Polymer Materials ◽  
Material Structure ◽  
New Approach ◽  
Time Frequency ◽  
Structure Assessment ◽  
Processing Techniques ◽  
Short Time ◽  
Signal Processing Techniques ◽  
Structure Inhomogeneity

Paper describes new approach to material structure analysis by means of ultrasound probing. Short-time Fourier transform and time-frequency analysis used to determine structure inhomogeneity present and perform structure condition assessment. Experimental results show possibilities of polymer materials structure assessment.

Mechanical Performance and Fracture Behavior of Recycled AA6061-T6 Alloy Melted from Aluminium Chips

2017 ◽  
Vol 7 (1) ◽  
pp. 1-17
Author(s):  
Naveed Akhtar ◽  
Razzaq Ahmed ◽  
Muhammad Arfan ◽  
Muhammad Noshad Ali
Keyword(s):  
Mechanical Properties ◽  
Intermetallic Compounds ◽  
Fracture Behavior ◽  
Mechanical Performance ◽  
Sem Analysis ◽  
Reverberatory Furnace ◽  
Molten Bath ◽  
Furnace Charge ◽  
Mixed Nature

Aluminium chips were re-melted under the molten bath in a gas fired reverberatory furnace and superior quality recycled AA6061-T6 alloy was synthesized. The chips were added 5 to 20% by weight in the recycled alloy. The furnace charge included clean scrap of the same alloy (AA6061) along with the machining chips or tunings of mixed nature. The chips used in this study were mostly generated from lath/bore operations carried on homogenized billets. The fabricated alloy of each heat was characterized for microstructures, mechanical properties and fracture behavior. The results showed that the metallurgical and mechanical performance of the recycled alloy was comparable to the primary alloy. However, SEM analysis of the recycled alloy revealed a sizeable amount of Fe and Si containing intermetallic compounds such as AlFeSi, AlFeMg, and AlSiMg phases.

scholarly journals Backbone cup – a structure design competition based on topology optimization and 3D printing

2016 ◽  
Vol 7 ◽  
pp. A1 ◽  
Author(s):  
Ji-Hong Zhu ◽  
Kai-Ke Yang ◽  
Wei-Hong Zhang
Keyword(s):  
Topology Optimization ◽  
3D Printing ◽  
Experimental Approach ◽  
Mechanical Performance ◽  
Turnaround Time ◽  
Structure Design ◽  
The Finite Element Method ◽  
New Approach ◽  
Design Competition ◽  
Testing Approach

This paper addresses a structure design competition based on topology optimization and 3D Printing, and proposes an experimental approach to efficiently and quickly measure the mechanical performance of the structures designed using topology optimization. Since the topology optimized structure designs are prone to be geometrically complex, it is extremely inconvenient to fabricate these designs with traditional machining. In this study, we not only fabricated the topology optimized structure designs using one kind of 3D Printing technology known as stereolithography (SLA), but also tested the mechanical performance of the produced prototype parts. The finite element method is used to analyze the structure responses, and the consistent results of the numerical simulations and structure experiments prove the validity of this new structure testing approach. This new approach will not only provide a rapid access to topology optimized structure designs verifying, but also cut the turnaround time of structure design significantly.

Study of a novel co-rotating non-twin screw extruder in processing flame retardant polymer materials

2017 ◽  
Vol 37 (8) ◽  
pp. 827-835
Author(s):  
Song Zhao ◽  
Baiping Xu ◽  
Liang He ◽  
Huiwen Yu ◽  
Shouzai Tan
Keyword(s):  
Flame Retardant ◽  
Mechanical Performance ◽  
Acrylonitrile Butadiene Styrene ◽  
Operating Conditions ◽  
Polymer Materials ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Limiting Oxygen Index ◽  
Twin Screw ◽  
Halogen Free

Abstract A thorough study was carried out to investigate the priority of a novel co-rotating non-twin screw extruder (NTSE) over a traditional twin screw extruder (TSE) in the mixing process of halogen-free intumescent flame-retardant acrylonitrile-butadiene-styrene (ABS) composites. The homogeneity of the flame-retardant additives of the composites processed by NTSE and TSE under the same operating conditions was characterized by using mechanical performance properties, limiting oxygen index values, UL-94 tests, and thermogravimetric analysis. All the results suggested that NTSE could achieve better mixing of the flame-retardant additives in the polymer matrix than TSE, which was further clarified by the scanning electron microscope pictures.

scholarly journals An Overview of the Main Trends in the Creation of Biodegradable Polymer Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Irina N. Vikhareva ◽  
Evgeniya A. Buylova ◽  
Gulnara U. Yarmuhametova ◽  
Guliya K. Aminova ◽  
Aliya K. Mazitova
Keyword(s):  
Raw Materials ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
New Approach ◽  
Renewable Raw Materials ◽  
Biodegradable Composite ◽  
Operational Characteristics ◽  
Technical Solutions ◽  
Further Development ◽  
Degradation Time

Plastic is one of the most demanded materials on the planet, and the increasing consumption of which contributes to the accumulation of significant amounts of waste based on it. For this reason, a new approach to the development of these materials has been formed: the production of polymers with constant operational characteristics during the period of consumption and capable of then being destroyed under the influence of environmental factors and being involved in the metabolic processes of natural biosystems. The paper outlines the prerequisites for the development of the field of creating biodegradable composite materials, as well as the main technical solutions for obtaining such polymeric materials. The main current solutions for reducing and regulating the degradation time of polymer materials are presented. The most promising ways of further development of the field of bioplastics production are described. Common types of polymers based on renewable raw materials, composites with their use, and modified materials from natural and synthetic polymers are considered.

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