Suppressing the skin–core structure in injection-molded HDPE parts via the combination of pre-shear and UHMWPE

RSC Advances ◽  
2015 ◽  
Vol 5 (103) ◽  
pp. 84483-84491 ◽  
Author(s):  
Zhen Wang ◽  
Guoqiang Zheng ◽  
Bo Wang ◽  
Kun Dai ◽  
John Zhanhu Guo ◽  
...  

Skin–core structure of a injection-molded high density polyethylene (HDPE) part is largely relieved due to the synergetic effects of pre-shear and UHMWPE, leading to a remarkable increase of tensile strength.

Author(s):  
Peter F. Baumann ◽  
Lucas Sendrowski

Large recycled high-density polyethylene (HDPE) structural members, difficult to manufacture by extrusion processes, have been created by the hot plate welding of simple plastic lumber sections. Hot plate welding generates better joint strength than any other welding method currently employed in plastic manufacturing. However, to achieve the desired temperature of the thick plate to melt the polymer uniformly, the process needs a high amount of heat energy requiring furnace (or resistance) heating of a considerable mass. A new method which could combine the heating element and a thin plate into one source could be more efficient in terms of heat loss and thus energy used. The premise of this investigation is to replace the hot plate with a very thin piece of high resistance nickel-chromium alloy ribbon to localize the application of heat within a plastic weld joint in order to reduce energy loss and its associated costs. This resistance ribbon method uses electrical current to reach an adequate temperature to allow for the welding of the HDPE plastic. The ribbon is only slightly larger than the welding surface and very thin to reduce the loss of excess heat through unused surface area and thick sides. The purpose of this project was to weld recycled high-density polyethylene (HDPE) using resistance welding and to match the tensile strength results considered acceptable in industry for hot plate welding, that is, equal to or greater than 80% of the base material strength. Information obtained through literature review and previous investigations in our laboratories established welding (heating) temperature and time as testing factors. Designed experimentation considered these factors in optimizing the process to maximize the weld tensile strength. A wide-ranging full-factorial experimental design using many levels was created for the initial testing plan. Tensile strengths obtained after welding under the various condition combinations of weld temperature and time revealed a region of higher strength values in the response surface. After the wide-range initial testing, the two control parameters, heating temperature and heating time, were ultimately set up in a focused Face Centered Cubic (FCC) Response Surface Method (RSM) testing design and the tensile strength response was then analyzed using statistical software. The results obtained indicated a strong correlation between heating time and heating temperature with strength. All welded samples in the final testing set exhibited tensile strength of over 90% base material, meeting the goal requirements. A full quadratic equation relationship for tensile strength as a function of welding time and temperature was developed and the maximum tensile strength was achieved when using 280°C for 60 seconds.


Author(s):  
Abdulmumin Adebisi ◽  
Tajudeen Mojisola ◽  
Umar Shehu ◽  
Muhammed Sani Adam ◽  
Yusuf Abdulaziz

In-situ synthesis of high-density polyethylene (HDPE) reinforced groundnut shell particulate (GSP) composite with treated GSP within the range of 10-30 wt% at 10 wt% has been achieved. The adopted technique used in the production of the composite is melt mixing and compounding using two roll mills with a compression moulding machine. Properties such as hardness, tensile strength, impact energy and water absorption analysis were examined. The result revealed that addition of GSP increases the hardness value from 22.3 to 87 Hv. However, the tensile strength progressively decreased as the GSP increases in the HDPE. This trend arises due to the interaction between neighbouring reinforced particulate which appears to influence the matrix flow, thereby inducing embrittlement of the polymer matrix. It was also observed that water absorption rate steadily increased with an increase in the exposure time and the absorbed amount of water increases by increasing the wt% of the GSP. Analysing the obtained results, it was concluded that there were improvements in the hardness, tensile strength, impact energy and water absorption properties of the HDPE-GSP polymer composite when compared to unreinforced HDPE. On these premises, GSP was found as a promising reinforcement which can positively influence the HDPE properties of modern composites.


2019 ◽  
Vol 33 (11) ◽  
pp. 1466-1477
Author(s):  
Qingfa Zhang ◽  
Wenyu Lu ◽  
Liang Zhou ◽  
Donghong Zhang ◽  
Hongzhen Cai ◽  
...  

Biocomposites were prepared with corn straw slagging (CSS) and high-density polyethylene (HDPE) at four loading levels (10, 20, 30, and 40 wt%) by extrusion method. CSS/HDPE composites were tested by tension, oxygen index meter, differential scanning calorimetry, X-ray diffraction, and the scanning electron microscopy. The scanning electron microscopy showed that CSS was dispersed uniformly in the HDPE matrix and strong interfacial interaction was achieved, which had an important influence on the tensile strength of the composites. The tensile strength of the composites could be improved with proper increase of CSS and reached maximum value at 30 wt% content. Furthermore, the addition of CSS played an important role in improving the flame-retardant ability of CSS/HDPE composites, and the limited oxygen index was 31.26% at 40 wt% content, good flame-retardant effect achieved.


Author(s):  
Jicheng Gao ◽  
Chao Li ◽  
Yifu Shen

The aim of this work is to fabricate the high-density polyethylene–copper composites by submerged friction stir processing at different traverse speeds. The scanning electron microscopy is used to analyze the distribution of microstructure and particles. The experimental results indicated that the macrostructure morphology, microstructure and tensile strength vary depending on the traverse speed. Compared with the pure high-density polyethylene, Cu-filled polymer composites showed lower tensile strength and higher microhardness. The maximal values of the tensile strength and microhardness were achieved at traverse speeds of 30 and 15 mm/min, respectively. The thermal properties of Cu-filled high-density polyethylene composites were studied by differential scanning calorimetry. The crystalline content of the composites was decreased due to the addition of copper. From the experimental tests, it can be concluded that submerged fiction stir processing has a great potential for producing polymer–metal composites.


2017 ◽  
Vol 756 ◽  
pp. 35-43
Author(s):  
Martin Bednarik ◽  
Adam Skrobak ◽  
Vaclav Janostik

This study deals with the effect of high doses of ionizing beta radiation (132, 165 and 198 kGy) on mechanical properties (tensile strength, tensile modulus and elongation) of low and high density polyethylene under thermal loading. The measurement results of this study indicate that with an increasing dose of radiation grows tensile strength and modulus of low and high density polyethylene. For all examined materials were also observed changes in elongation.


2015 ◽  
Vol 754-755 ◽  
pp. 201-204
Author(s):  
Ragunathan Santiagoo ◽  
Sam Sung Ting ◽  
Azlinda Abdul Ghani ◽  
Hanafi Ismail ◽  
Awiezan Mislan

The compatibilizer effect of ENR-50 on the tensile properties of high density polyethylene (HDPE)/recycled acrylonitrile butadiene rubber (NBRr)/banana skin powder (BSP)/ composites has been studies. HDPE/NBRr/BSP composites were prepared by melt mixing technique using twin-screw at 180 °C for 9 minutes at rotor speed 50 rpm. The six different composites studied were 100/0/5, 80/20/5, 70/30/5, 60/40/5, 50/50/5, and 40/60/5. As for compatibilized composite a fix 5 wt% of ENR-50 was evaluated. The specimens were analysed for tensile strength and elongation at break (Eb). The results showed that tensile strength and the elongation at break were decreases with the increasing of NBRr loading. However for ENR-50 compatibilized composites, higher tensile strength and elongation at break was recorded. The ENR-50 was found to be an excellent compatibilizer for HDPE/NBRr/BSP composites.


2014 ◽  
Vol 695 ◽  
pp. 48-51
Author(s):  
Aris Noor Fatheyah ◽  
A. Majid Rohah ◽  
Mohamad Darus Mohana Hasniza ◽  
Wan Hassan Wan Hasamuddin

Palm pressed fibre (PPF) with particle size of 200 micron was utilized as a filler to produce environment friendly biocomposite film. PPF contains 5-6% oil residue after the oil extraction process and the oil can be used as a lubricant to assist the distribution of PPF throughout the matrix of plastic resin during processing. In this study, high density polyethylene (HDPE) plastic resin was incorporated with untreated PPF at four different weight percentages namely, 5, 10, 15 and 20 wt%. Each mixture was compounded via twin screw extruder prior to compression moulding into film sheets with thickness of 0.15mm. Maleic anhydride (MAH) and glycerol were used as compatibilizer and plasticizing agents. The effect of PPF loading on the tensile strength and the surface morphology were the main interest. It was found that by increasing the PPF contents had increased the stiffness of the films but reduced the tensile strength and elongation at break due to weak interfacial adhesion between HDPE matrix and PPF. This was probably due to insufficient amount of MAH to compatabilize the increasing amount of PPF, thus resulting non-uniform PPF distribution across the HDPE matrix. The findings were supported by SEM micrographs which showed rough surface and the disruption of the continuous phase of HDPE matrix, thus weakening the strength and flexibility of the samples. HDPE/PPF biocomposite has a potential to be used in agriculture sectors such as mulching film.


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