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The purpose of this article is to discuss the tribological behavior of polytetrafluoroethylene (PTFE) and property changes imposed by wear tests.

Long-duration dry wear tests were carried out in a sliding bearing on shaft tribometer. Differential Scanning Calorimetry (DSC) and Fourier Transformed Infrared Spectroscopy (FTIR) analyses were performed in the PTFE in its original condition and after the tests.

The wear products merged in multilayer films and were expelled out of the test sequence. Through DSC and FTIR analyses in the polymeric material, before and after tests, it was possible to verify an increase of the crystallinity degree of PTFE, as well as absence of crystalline fusion of the material. The wear products presented changes in the infrared spectra, which suggests the occurrence of some bonds of hydrogen and oxygen.

It was verified on correlation that fibril mechanism, which occurred during PTFE wear, and its crystallinity degree increase. Also, analysis of PTFE wear products showed CO and CH bonds, which were imposed by wear test.

Although the feasibility and effectiveness of the fused deposition modeling (FDM) method have been proposed and developed, studies of applying this technology to various materials are still needed for researching its applicability, especially with regard to polymer blends and composites. The purpose of this paper is to study the deposition-induced effect and the effect of compatibilizers on the mechanical properties of polypropylene and polycarbonate (PP/PC) composites.

For this purpose, three different deposition modes for PP/PC composites with or without compatibilizers were used for the FDM method and tested for tensile properties. Also, parts with the same materials were made by injection molding and used for comparison. In addition, different deposition speeds were used to investigate the different deposition-induced effects. Furthermore, the behavior of the mechanical properties was clarified with scanning electron microscope images of the fracture surfaces.

The research results suggest that the deposition orientation has a significant influence on the mechanical behavior of PP/PC composite FDM parts. The results also indicate that there is a close relationship between the mechanical properties and morphological structures which are deeply influenced by compatibilization. Compared with injection molded parts, the ductility of the FDM parts can be dramatically improved due to the formation of fibrils and micro-fibrils by the deposition induced during processing.

This is the first paper to investigate a PP/PC composite FDM process. The results of this paper verified the applicability of PP/PC composites to FDM technology. It is also the first time that the deposition-induced effect during FDM has been investigated and studied.

Focusses on preliminary studies on developing thermoplastic composite materials suitable for use in fused deposition modeling (FDM). Looks at thermotropic liquid crystalline polymers (TLCPs). Specifically aims to determine the feasibility of post‐processing TLCP composite strands generated by means of the dual extrusion process using FDM to enhance the tensile properties and functionality of prototypes. Describes the experiments and gives in‐depth results which include the finding that final mechanical properties of a composite prototype can be tailored to a specific application by adjusting the laydown pattern to increase the functionality of the prototype, and that these properties can be predicted by composite theory.

The purpose of this paper is to acquaint the readers with recent developments in biopolymer-based food packaging materials like natural biopolymers (such as starches and proteins), synthetic biopolymers (such as poly lactic acid), biopolymer blending and nanocomposites grounded on natural and synthetic biopolymers. This paper is an attempt to draw the readers towards the advantages and attributes of new era polymers to diminish the usage of traditional non-biodegradable polymers.

Plastic packaging for food and associated applications is non-biodegradable and uses up valuable and treasured non-renewable petroleum products. With the current focus on researching alternatives to petroleum, research is progressively being channelized towards the development of biodegradable food packaging, thereby reducing adverse impact on the environment.

Natural biopolymer-based nanocomposite packaging materials seem to have a scintillating future for a broad range of applications in the food industry, including advanced active food packaging with biofunctional attributes. The present review summarizes the scientific information of various packaging materials along with their attributes, applications and the methods for production.

This is an apropos review as there has been a recent renewed concern in research studies, both in the industry and academe, for development of new generation biopolymer-based food packaging materials, with possible applications in many areas.

A series of all-atom molecular-level computational analyses is carried out in order to investigate mechanical transverse (and longitudinal) elastic stiffness and strength of p-phenylene terephthalamide (PPTA) fibrils/fibers and the effect various microstructural/topological defects have on this behavior. The paper aims to discuss these issues.

To construct various defects within the molecular-level model, the relevant open-literature experimental and computational results were utilized, while the concentration of defects was set to the values generally encountered under “prototypical” polymer synthesis and fiber fabrication conditions.

The results obtained revealed: a stochastic character of the PPTA fibril/fiber strength properties; a high level of sensitivity of the PPTA fibril/fiber mechanical properties to the presence, number density, clustering and potency of defects; and a reasonably good agreement between the predicted and the measured mechanical properties.

When quantifying the effect of crystallographic/morphological defects on the mechanical transverse behavior of PPTA fibrils, the stochastic nature of the size/potency of these defects was taken into account.

Mycelium is an upcoming bio-based alternative material that has various applications in different industries. Mycelium materials used as composites, leather, construction materials and some are even available for commercial purposes. However, there was not much research found when it came to the application of mycelium as a textile alternative. The purpose of this paper is to examine the potential of mycelium in the textile industry and its possible applications.

This review consolidates literature that refers the two major methods used in fungal mycelium production namely; as a composite and as a pure self-grown mycelium sheet. The study compared the current research status in this respective field and reported the scope in the pure mycelium development.

The results of the review reported that several research works are performed in composite production with different feedstock. The production methods and product development steps were well established for several applications from home utilities to construction materials. Whereas, in the case of self-grown mycelium sheet production only limited research works were found. Though the possibilities of engineered composite sheets are developed with various properties, research on self-grown pure mycelium sheets are at infant stage. Sensitive production methods, lower tensile, tearing, poor handle properties with brittle structure and non-uniformity in thickness are noted as limitations. Sustainable nature, self-grown three-dimensional nano-fibril network with porous structure are found to be advantageous.

The solid culture method was identified as a potential method to develop a sheet-like self-grown mycelium with different dimensions. The review results clearly show the lack of research in the direct application of self-grown pure mycelium area concerning feedstock material, fungal species selection and characterization of the developed product. Addressing the existing limitations will yield a sustainable textile material for fashion and textile industry with great potential.

This paper aims to provide a detailed study on influence of the laser energy density on mechanical, surface and dimensional properties of polyamide 12 (PA12) parts produced by selective laser sintering (SLS), providing the microstructural and crystallization evolution of the samples produced at different energy densities.

Making use of a space filling design of experiments, a wide range of laser sintering parameters is covered. Surface morphology is assessed by means of profile measurements and scanning electron microscopy (SEM) images. Mechanical testing, SEM, X-ray diffraction (XRD), differential scanning calorimeter (DSC) and infrared spectroscopy (FTIR) were used to assess the influence of energy density on structural and mechanical properties.

Results show a high dependency of the properties on the laser energy density and also a compromise existing between laser exposure parameters and desired properties of laser sintered parts. Surface roughness could be associated to overlap degree when using higher scan line spacing values and lower laser speeds improved surface roughness when high scan line spacing is used. Higher mechanical properties were found at higher energy density levels, but excessively high energy density decreased mechanical properties. A transition from brittle to ductile fracture with increasing energy density could be clearly observed by mechanical analysis and SEM. XRD and DSC measurements show a decrease on the crystal fraction with increasing energy densities, which corroborated the plastic behavior observed, and FTIR measurements revealed polymer degradation through chain scission might occur at too high energy densities.

Valuable guidelines are given regarding energy density optimization for SLS of PA12 considering not only quality criteria but also microstructure characteristics. Surface properties are studied based on the concept of degree of overlap between laser scanning lines. For the first time, crystallization behavior of SLS PA12 parts produced at different energy levels was studied by means of XRD measurements. Polymer degradation of SLS PA12 parts was evaluated with FTIR, which is a non-destructive and easy test to be conducted.

Time and Motion Study, as its name implies, has always advocated the integration of all Work Study interests. It has always held the view that Motion Study and Time Study are complementary to one another.

Examines the tenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

Fatigue and creep are the key factors for the failure of polymethyl methacrylate (PMMA) in the engineering structure, so a great of quantity attention is focused on the life prediction under the creep and fatigue conditions. This paper aims to mainly summarize the traditional life assessment method (S–N curve), life assessment method based on crazing density and life assessment method based on transmittance. S–N curve and classical creep curve are introduced on the traditional life assessment method; the variation of the craze density with the logarithm of cyclic numbers is given in different fatigue load. A linear relationship is obtained, and a higher stress leads to a higher slope, suggesting a faster growth of craze. Furthermore, a craze density model is purposed to describe this relationship; the variation of craze density with the time at different creep load is given. The craze density has two obvious stages. At the first stage, craze density ranged from approximately 0.02 to 0.17, and a linear relationship is obtained. In the following stage, a nonlinear relationship appears till specimen rupture, a new creep life model is proposed to depict two stages. The relationship between transmission and time under creep load is shown. With increasing of time, the transmittance shows a nonlinear decrease. Through polynomial nonlinear fitting, a relationship between the transmittance and residual life can be obtained. To provide reference for the life assessment of transparent materials, the paper compares three life assessment methods of PMMA.

This paper uses the traditional life assessment method (S–N curve), life assessment method based on crazing density, life assessment method based on transmittance.

The variation of the craze density with the logarithm of cyclic numbers is given in different fatigue loads. A linear relationship is obtained, and a higher stress leads to a higher slope, suggesting a faster growth of craze. Furthermore, a craze density model is proposed to describe this relationship, and the variation of craze density with the time at different creep loads is given. The craze density has two obvious stages. The relationship between transmission and time under creep load is shown. With increasing of time, the transmittance shows a nonlinear decrease. Through polynomial nonlinear fitting, a relationship between the transmittance and residual life can be obtained.

Fatigue and creep are the key factors for the failure of PMMA in the engineering structure, so a great of quantity attention is focused on the life prediction under the conditions of creep and fatigue. This paper mainly summarizes traditional life assessment method (S–N curve), life assessment method based on crazing density and life assessment method based on transmittance.