Papers by Keyword: Thermoplastic Elastomer

Abstract: The influence of filler type and content on the wettability and interfacial bonding between thermoplastic elastomer (TPE) and polypropylene (PP) by using the injection overmolding process was investigated in this study. Calcium carbonate (CaCO₃) and talcum (Talc) masterbatchs, ranging from 0 to 40 percent by weight (wt%), were mixed into the PP matrix as fillers. The bond strength of TPE overmolded onto PP composites was characterized by the tensile and tear tests. Good compatibility was observed between TPE and PP filled with various amounts of CaCO₃ and Talc. In the case of the tensile test, the crack initiation stress, ultimate tensile strength, strain at break, and bond energy were found to decrease with increasing filler content. The results obtained from the tear test indicated that the propagation strength, ultimate tear strength, strain at break, and bond energy of injection overmolded TPE-PP filled with various CaCO₃ contents did not significantly change compared to those obtained from Talc. This can be attributed to the high reinforcing efficiency of Talc in comparison with CaCO₃, which can enhance the stiffness and thermal resistance of the PP matrix. As a result, the contact area becomes more resistant to molecular diffusion of TPE chains, particularly at high Talc loadings (30 and 40 wt%), leading to the reduction of interfacial bonding.

Abstract: This study explores the feasibility of utilizing a thermoplastic elastomer seal made from a blend of rubber and recycled polypropylene (PP) derived from disposable plastic bottles. Thermoplastic elastomers develop by blending natural rubber (NR), epoxidized natural rubber (ENR), and maleated natural rubber (MNR) with PP in a 60/40 rubber-to-PP ratio. The results indicate that NR exhibits superior tensile strength, tear resistance, and compression set compared to ENR and MNR, attributed to NR's crystallization upon stretching and its inherent high elasticity. Both NR and ENR demonstrated good ozone resistance with no observed cracking, while MNR showed the lowest resistance, evidenced by visible cracks after the ozone explosion. NR emerged as the most suitable rubber for thermoplastic elastomer preparation, outperforming ENR and MNR. Comparative analysis between the prototype and commercial products revealed that the prototype's mechanical properties, ozone resistance, and thermal degradation resistance were largely comparable to those of the commercial counterparts. However, to improve flame resistance, further development is needed, particularly through the incorporation of flame-retardant additives.

Abstract: Co-Pоly (Urethane-Imide) s (CPUI) based on pоly (diethyleneglycol) adipate diol, tolylenediisocyanate, multinucleate dianhydrides and diamines were synthesized. The films and moldings from CPUI were processed and their mechanical characteristics were evaluated. Distinctions of specifications of the films formed from polymer solutions and the moldings formed from melt polymers are indicated when using the same starting CPUI. It appears that films and moldings possess typical properties of elastomers. The reprocessing of studied copolymers by using the injection molding method allows to assign CPUI to the thermoplastic elastomers or so-called thermoelastoplasts.

Abstract: This paper presents the results of the study of the effect of polymer materials compression and injection methods of molding on the physical and mechanical properties of the resulting samples. Widely used polymers such as poly-amide, thermoplastic elastomer and polyketone were taken as the objects of study. Granite composites based on polyamide were produced by PolyLab Rheomex RTW 16 twin-screw extruder, then modified with fine powders of schungite, graphite and silicon dioxide. Samples for testing in the form of double-sided blades were obtained by injection molding on a Babyplast 6/10V machine and compression molding on a Gibitre hydraulic press. Elastic-strength tests of the obtained samples were carried out on a tensile testing machine UAI-7000 M.

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: The main drawback of low-density polyethylene (LDPE) film for packaging of fresh fruit or vegetables is low moisture breathability. This study developed breathable films by blending LDPE with thermoplastic polyester elastomer (TPEE). LDPE and TPEE in the weight ratios of 95/5, 90/10, 80/20, 70/30, and 60/40 wt% were melt blended and then extruded into films using a cast film extruder. Clarity of films was characterized by UV-VIS spectroscopy. Tensile properties, tear resistance, the degree of crystallinity, and morphology of blend films were evaluated. Water vapour transmission rate (WVTR) was investigated using a desiccant method. The prepared films were transparent. However, the UV-VIS transmittance was reduced slightly. Blending TPEE of more than 10 wt% reduced the modulus but increased elongation at break. It did not impact on the tensile strength of the blends. Since LDPE and TPEE are immiscible, applied stress during extrusion pulled them apart at the interphase boundaries creating micro-pores. As a result, these micro-pores reduce tear resistance significantly but increase WVTR of the blend films. Using a blend ratio of 90/10 wt%, the effect of chill-roll temperature and nip-roll velocity on film properties were studied. It was found that nip-roll velocity had more influence on WVTR than chill-roll temperature due to elongation of the pores.

Abstract: Injection molding is one of the most extended plastic processing technologies. Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. This paper shows the influence of mold cavity surface roughness and technological parameters on the flow length of thermoplastic elastomers and rubber into mold cavity. The fluidity of polymers is affected by many parameters (mold design, melt temperature, injection rate and pressures) and by the flow properties of polymers. Evaluation of the data obtained by experiments where the testing conditions were widely changed shows that quality of the cavity surface does not affect the length of flow.

Abstract: Thermoplastic polyurethane/graphene nanocomposites were successfully prepared by mixing masterbatches with neat polymers using the melt compounding process. Graphene was obtained from graphite by the chemical mean. Graphite was initially converted into graphite oxide which was then converted to graphene oxide. Graphene oxide was then reduced by L-ascorbic acid to obtain graphene. The effects of graphene addition on thermal and morphological properties of nanocomposite were studied by a differential scanning calorimeter, a thermal gravimetric analyzer and a scanning electron microscope. TPU/graphene nanocomposites showed higher melting temperature compared to TPU. On the other hand, heat of fusion of nanocomposites was lowered. TPU and TPU/graphene nanocomposites have two steps of decomposition. The first degradation of TPU occurred at higher temperature compared with nanocomposites but the second degradation showed the opposite results. The percentage of residue after thermal degradation of nanocomposites was lower than that of TPU. For surface morphology, nanocomposite exhibited the rougher surface comparing with TPU and well graphene dispersion in TPU phase was achieved. Nevertheless, there were some agglomeration of graphene.

Abstract: The paper experimentally studies the effect of meta and para- substitution of the amino groups in the diamine used in the synthesis of multiblock copolymers. The way for synthesis of new multiblock copolymers with the possibility of replacing the diamine in the polymer structure was shown. Thermal and mechanical properties of synthesized copolymers had been characterized by means of differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis and by nanoindentation and tensile test.

Abstract: Polymer blending is one of the methods used to improve some insufficient properties of conventional polymers. The objective of this work was to study the effectiveness of CR content on the tensile properties and morphology study of recycled polypropylene (rPP)/ chloroprene rubber (CR) blends. The results indicated that the tensile strength and modulus of elasticity of rPP/CR blends decreased, however elongation at break increased as increasing CR content. The morphology study of rPP/CR blends showed the incompatibility between rPP and CR with the detachment of CR particles and CR particles pulled out from rPP surface.