Papers by Keyword: Thermoplastics

Abstract: 3D printing is emerging in the healthcare field. Being able to reproduce organ models with low-cost and sustainable technology is generating a big impact on professionals working in the medical industry. This work aims to illustrate the potential of the material extrusion technique by replicating 3D models used for helping surgeons in pre-operative planning. The properties of a standard thermoplastic PLA for 3D printing are compared with other thermoplastics with elastomeric properties whose application is arising nowadays in this field, namely PEBA, TPO, and TPU. This research covers three real cases of study: a pulmonary fistula, a bone tumor, and a replication of the spinal column. The cases helped anticipate potential problems during surgery and achieve good quality in educating and training new professionals. Finally, an optimal printing configuration is presented. The settings of the printing parameters selected are the ones that maximize the inter and intra-layer bonding, which is important to achieve good shape results and consistency of the models. Although the printed parts are not meant to support a big mechanical effort, it is important to relate the selection of the printing parameters to the adhesion of filaments in order to reduce the quantity of material deposited during the manufacturing process, and consequently, reduce the printing time. Also, to achieve a realistic model that can be of effective help for the medical faculty when preparing their interventions and during their diagnostic process.

Abstract: This paper studies deployable elements which are used in satellites and different terrestrial antenna devices. Many deployable elements are made from steel or thermoset polymer composite materials and have the following disadvantages like length limitation of deployable elements, labour intensity of manufacturing process of deployable elements etc. For this purpose a deployable tube boom element was chosen and a forming method for manufacturing deployable tube element from thermoplastic polymer composite material was developed.

Abstract: The series of compositions containing thermodynamically incompatible flexible blocks of aliphatic polyesters and rigid blocks of aromatic bis (urethane) imides in the volume of polymers was obtained on the basis of multiblock (segmented) poly (urethane-imides) and related aromatic polyimides. The series includes segmented poly (urethane-imides) with different relative content of flexible and rigid blocks, non-segregating mixtures of poly (urethane-imides) and thermoplastic partially crystalline polyimide, statistical copolymers of poly (urethane-imide) with imide, and non-segregating mixtures of statistical copolymers with thermoplastic polyimide. The derived polymer systems were studied using thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The deformation and strength properties of film samples are determined. It is shown that the properties of the studied polymers change as their content of imides blocks increases, and the transition from thermoplastic poly (urethane-imide) elastomers to thermoplastic polyimides is observed.

Abstract: This article deals with comparative analysis between thermoplastics and thermosets polymer materials. The problems of the choice of the polymer matrix and reinforcement filler in the manufacture products are made of polymer composite materials (PCM) for the oil industry are considered. Based on the analysis of existing types of polymer matrix and reinforcement fillers to maximize the requirements for PCM products for the oil and gas industry, a polyphenylene sulfide feed was proposed as a polymer matrix, and a unidirectional carbon fiber was used as a reinforcement filler. The results of laboratory tests of samples made with the help of melt impregnation and automated fiber placement technologies are presented.

Abstract: The results of experimental studies of a new method for turning billets from thermoplastic polymers such as caprolon and fluoroplastic are presented. The technical essence of the method is in workpiece advanced processing by ultrasonic vibrations using preliminary machining. Experimental studies were carried out on a lathe which is equipped with an ultrasonic oscillatory system. Roughness level profilograms of the caprolon and fluoroplastic treated surfaces are used for visual and operational control of the turning process. The results of the experimental verification of the developed method confirmed the expediency of its implementation since the use of advanced ultrasonic treatment during turning of thermoplastics leads to a decrease in the roughness level of the treated surface of the part as evidenced by the values ​​of roughness parameters and the type of chips obtained.

Abstract: In order to sustainably establish carbon fiber reinforced polymer composites (CFRPC) in the market on an industry scale, solutions on how to recycle these new materials have to be developed. Quasi-continuously aligned carbon staple fiber structures in organic sheets made of recycled carbon are one approach which will be dealt with in this article. The process chain as well as the mechanical properties will be presented. Moreover, the specific feature of staple fiber yarns to be able to plastically deform under process temperature, enabling new degrees of deep-drawing of CFRPC organic sheets in the thermoforming process, will be highlighted.

Abstract: Synthesis of poly (1, 4-phenylene sulfide) (PPS) through oxidative polymerization seems promising to us. Comparing with current commercial method to poly (1, 4-phenylene sulfide) from 1, 4-phenylene sulfide and sodium sulfide (Phillips’ Method), there are many advantages of the oxidative polymerization method. For example, it can synthesize PPS at normal temperature and pressure; the yield of reaction is very high; it provides pure PPS without salt contamination. However, several years have passed away; synthesis of poly (1, 4-phenylene sulfide) through oxidative polymerization has not so far been adopted as the industrial process. Many of us are puzzled, why Through studying all kinds of reported preparation route to poly (1, 4-phenylene sulfide) through oxidative polymerization compared to Phillips’ Method, a generic polymerization mechanism is achieved for most of them excepting two with obvious shortcomings. We suddenly realize that synthesis of poly (1, 4-phenylene sulfide) through oxidative polymerization seems unsuitable to be used in industrial production recently because of its own limits.

Abstract: This article is focused on the field of computer simulation and it is subsequent verification in practice. The work highlights the injection process, the simulation software that is specialized in injection molding and the technology process of injection itself. The major subject of the thesis is the use of the computer aided injection molding technology by using the CAE systems. The experimental part of the thesis deals with the production of the 3D model specific plastic parts in two modifications, injection molding simulation in the system Moldex3D and digitization of moldings on the optical 3D scanner. In the thesis we also provide measuring realization on digitized models and comparison of the parts size with the computer model. In conclusion we summarize the results achieved from the comparison. The thesis is carried out in cooperation with the Simulpast s.r.o.

Abstract: The Fibre Reinforced Plastic (FRP) composites are extensively used for a wide variety of applications in automobile, aerospace, chemical, biomedical and civil engineering fields due to their excellent properties. Composite materials offer significant advantages in strength-to-weight ratio and corrosion resistance over metallic materials. Initially FRP composites were based mainly on thermoset polymers because of the ease of manufacturing. But, recently FRP composites using thermoplastics matrices are gaining importance because of their advantages over thermoset composites. In the present work, FRP laminates were fabricated using glass fabric and carbon fabric as reinforcements and thermoplastic polymer (polypropylene) as matrix. Fiber Reinforced Thermoplastics (FRTP) laminates of glass fibre /polypropylene (GF/PP), carbon fibre/ polypropylene (CF/PP) and glass-carbon fibre /polypropylene (GF/CF/PP) hybrid composite laminates were fabricated by film stacking method using hot compression molding press under optimum process parameters (pressure, temperature and dwell time). The fabricated FRTP laminates were tested for various mechanical and physical properties viz., tensile strength/modulus, flexural strength/modulus, izod impact strength, moisture absorption, barcol hardness and density as per relevant ASTM standards. The results of the tests carried out on three materials were compared. It was observed that hybrid laminate (GF/CF/PP) is superior in flexural strength/modulus as compared to GF/PP but the little lower mechanical properties compared to CF/PP laminates. But use of hybrid laminates has great cost advantage compared to CF/PP.

Abstract: Hybrid laminates with thermoplastic matrices offer clear advantages over laminates based on thermosetting resins. These include the formability, recyclability as well as the suitability for mass production, to name a few. The inline integration of smart systems like sensors and actuators in the hybrid laminates during the hot-pressing process is one of the long-term objectives of the Federal Cluster of Excellence MERGE. This work aims to deposit Ni-C thin films by dc magnetron sputtering on polyimide substrates for the application as strain sensors in hybrid laminates. During the first step hybrid laminates containing different polyimide foils were prepared by hot-pressing, this was followed by the mechanical testing and selection of the most suitable polyimide substrate for the Ni-C thin film deposition. The second part consisted of depositing Ni-C thin films by means of dc magnetron sputtering and utilising different Ni-C plug targets. The films were characterised regarding their growth rate, composition, structure and temperature coefficient of electrical resistance.