scholarly journals Radiation-Based Crosslinking Technique for Enhanced Thermal and Mechanical Properties of HDPE/EVA/PU Blends

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2832
Author(s):  
Jang-Gun Lee ◽  
Jin-Oh Jeong ◽  
Sung-In Jeong ◽  
Jong-Seok Park

Crosslinking of polyolefin-based polymers can improve their thermal and mechanical properties, which can then be used in various applications. Radiation-induced crosslinking can be done easily and usefully by irradiation without a crosslinking agent. In addition, polymer blending can improve thermal and mechanical properties, and chemical resistance, compared to conventional single polymers. In this study, high-density polyethylene (HDPE)/ethylene vinyl acetate (EVA)/polyurethane (PU) blends were prepared by radiation crosslinking to improve the thermal and mechanical properties of HDPE. This is because HDPE, a polyolefin-based polymer, has the weaknesses of low thermal resistance and flexibility, even though it has good mechanical strength and machinability. In contrast, EVA has good flexibility and PU has excellent thermal properties and wear resistance. The morphology and mechanical properties (e.g., tensile and flexure strength) were characterized using scanning electron microscopy (SEM) and a universal testing machine (UTM). The gel fraction, thermal shrinkage, and abrasion resistance of samples were confirmed. In particular, after storing at 180 °C for 1 h, the crosslinked HDPE-PU-EVA blends exhibited ~4-times better thermal stability compared to non-crosslinked HDPE. When subjected to a radiation dose of 100 kGy, the strength of HDPE increased, but the elongation sharply decreased (80%). On the other hand, the strength of the HDPE-PU-EVA blends was very similar to that of HDPE, and the elongation was more than 3-times better (320%). Finally, the abrasion resistance of crosslinked HDPE-PU-EVA was ~9-times better than the crosslinked HDPE. Therefore, this technology can be applied to various polymer products requiring high heat resistance and flexibility, such as electric cables and industrial pipes.

2016 ◽  
Vol 852 ◽  
pp. 16-22
Author(s):  
S. Vishvanathperumal ◽  
S. Gopalakannan

Carbon black and silica have been used as the main reinforcing fillers that increase the usefulness of rubbers. In this work the effect of carbon black (high abrasion furnace)/silica hybrid fillers on the mechanical properties, crosslink density and morphological behaviour of ethylene vinyl acetate (EVA) was investigated. EVA reinforced with 0/50, 10/40, 20/30, 30/20, 40/10 and 50/0 phr of carbon black (CB)/silica hybrid filler. The total hybrid filler is kept constant at 50 phr (parts per hundred rubbers) and six different compounds were prepared. EVA, CB and silica followed by compounding on a two roll mill and molding at 180°C and 20 megapascal (MPa) pressure. The mechanical properties such as tensile & tear strength, elongation at break and 100% modulus have been measured at 23°C on universal testing machine. Abrasion resistance, hardness and rebound resilience are studied using DIN abrader, Shore A durometer and vertical rebound resilience respectively. The tensile strength, modulus, tear strength, abrasion resistance, hardness and crosslink density increased with the CB filler content in hybrid filler, reached the maximum value at 50 phr of high abrasion furnace carbon black. Morphological properties of composites were evaluated by scanning electron microscopy analysis.


2018 ◽  
Vol 210 ◽  
pp. 02038
Author(s):  
Martin Ovsik ◽  
Tomas Fiala ◽  
Miroslav Manas ◽  
Adam Dockal

This article deals with the use of Ultra-nano indentation Tester UNHT3 for the measurement of (ultra nano) mechanical properties. The effect of electron beam (EB) radiation on Polybutylene terephthalate (PBT) was investigated. To clarify whether crosslinking could take place without or only with the presence of a crosslinking agent, special attention was paid to the incorporation of this agent into tested polymer. In this study we have investigated the effect of crosslinking agent, and instantaneously electron beam radiation-induced crosslinking in the presence of Triallyl cyanurate on various mechanical properties of PBT. The results show that the influence of radiation has improved the observed properties in the surface layer. The increase in ultra-nano properties was around 26% over the basic material. Engineering plastics like Poly (butylene terephthalate) due to their desirable properties have various industrial applications.


Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1725
Author(s):  
Purba Purnama ◽  
Muhammad Samsuri ◽  
Ihsan Iswaldi

As one of the most attractive biopolymers nowadays in terms of their sustainability, degradability, and material tune-ability, the improvement of polylactide (PLA) homopolymer properties by studying the utilization of stereocomplex polylactide (s-PLA) effectively and efficiently is needed. In this sense, we have studied the utilization of s-PLA compared to poly D-lactide (PDLA) homopolymers as a nucleating agent for PLA homopolymers. The mechanical and thermal properties and crystallization behavior of PLA homopolymers in the presence of nucleating agents have been evaluated using a universal testing machine, differential scanning calorimeter, and X-ray diffractometer instruments, respectively. PDLA and s-PLA materials can be used to increase the thermal and mechanical properties of poly L-lactide (PLLA) homopolymers. The s-PLA materials increased the mechanical properties by increasing crystallinity of the PLLA homopolymers. PLLA/s-PLA enhanced mechanical properties to a certain level (5% s-PLA content), then decreased them due to higher s-PLA materials affecting the brittleness of the blends. PDLA homopolymers increased mechanical properties by forming stereocomplex PLA with PLLA homopolymers. Non-isothermal and isothermal evaluation showed that s-PLA materials were more effective at enhancing PLLA homopolymer properties through nucleating agent mechanism.


Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2393 ◽  
Author(s):  
Sanchez-Olivares ◽  
Sanchez-Solis ◽  
Manero ◽  
Pérez-Chávez ◽  
Jaramillo ◽  
...  

The high flame-retardant loading required for ethylene-vinyl acetate copolymer blends with polyethylene (EVA-PE) employed for insulation and sheathing of electric cables represents a significant limitation in processability and final mechanical properties. In this work, melamine triazine (TRZ) and modified bentonite clay have been investigated in combination with aluminum trihydroxide (ATH) for the production of EVA-PE composites with excellent fire safety and improved mechanical properties. Optimized formulations with only 120 parts per hundred resin (phr) of ATH can achieve self-extinguishing behavior according to the UL94 classification (V0 rating), as well as reduced combustion kinetics and smoke production. Mechanical property evaluation shows reduced stiffness and improved elongation at break with respect to commonly employed EVA-PE/ATH composites. The reduction in filler content also provides improved processability and cost reductions. The results presented here allow for a viable and halogen-free strategy for the preparation of high performing EVA-PE composites.


2020 ◽  
pp. 096739112093010
Author(s):  
Jawad Ahmed ◽  
Yong Zhang

The effect of electron beam (e-beam) irradiation on the thermal and mechanical properties of ethylene-vinyl acetate copolymer/ternary polyamide (EVA/tPA) blends was studied. The e-beam irradiation was carried out over a range of dose from 50 kGy to 500 kGy with trimethylolpropane trimethacrylate (TMPTMA) and triallyl isocyanurate (TAIC) as cross-linking coagents. With increasing irradiation dose, the gel fraction of the EVA/tPA blends increased significantly. After irradiated by e-beam at 500 kGy, the insoluble fraction of EVA/tPA blends with 3 parts per hundred rubber TMPTMA increased from 28% to 86%. The tensile strength of EVA/tPA/TMPTMA-3 (70/30/3) considerably increased up to 172% with a value of 10.01 MPa at 500 kGy due to an increase in cross-linking compared to the EVA/tPA/TAIC-3 (70/30/3) blend. However, the melting temperature and crystallization peak temperature of EVA/tPA blends decreased with increasing irradiation dose. Thermogravimetric analysis demonstrated that the irradiation cross-linking could improve the thermal stability of the EVA/tPA blends. The degradation kinetics of the EVA/tPA blends at elevated temperatures were studied using the Kissinger, Flynn–Wall–Ozawa, and Friedman methods. Irradiation cross-linked EVA/tPA blends exhibited a remarkable improvement in their oil resistance, with the identified improvement being most prominent in the EVA/tPA/TMPTMA-3 blend.


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