scholarly journals Deodorizing Methods for Recycled High-density Polyethylene Plastic Wastes

2021 ◽  
Vol 58 (3) ◽  
pp. 129-136
Author(s):  
Ho Dany ◽  
Wong Whui Dhong ◽  
Koh Weng Jiata ◽  
Tan Kiant Leong ◽  
Nor Yuliana Yuhana ◽  
...  

The recycling of high-density polyethylene plastic (HDPE) plays a crucial role in sustainable development. However, obstacles to the use of recycled HDPE remain because of the material and processing properties and odors of recycled HDPE. The odor of recycled detergent bottle plastic leads to rejection by most detergent manufacturers. Recently, some recycling enterprises have adapted recycling with odor reduction processes involving the use of solvents, antimicrobial additives, and odor extraction units in feeders and extruders. However, these processes may affect the quality and cost of recycled plastic. Most small and medium businesses (SMBs) may not favor these effects due to their limited models and resources. In addition, most SMBs are unwilling to replace their current recycling operation units. Hence, this study aimed to find alternative and economical ways for odor reduction in the recycling process. A modification of the recycling process was introduced in the pretreatment of plastic flakes before entry into the feeder of an extrusion unit. The effect of selected washing temperatures, i.e., 65℃, 75℃, 85℃, and 95℃, on the removal of odor from recycled HDPE was further studied. The addition of sodium bicarbonate, calcium carbonate, and citric acid into a heated water bath enhanced the deodorizing effect. The relationship of these three chemicals with the deodorization of HDPE plastics was investigated through sensory evaluation. Lastly, the potential of the deodorized recycled HDPE for resin pellet production and commercialization were investigated.

2020 ◽  
Vol 36 (3) ◽  
pp. 185-195 ◽  
Author(s):  
Negin Farshchi ◽  
Yalda K Ostad

Regarding the current demand for controlling plastic pollution, recycling of polymer sounds a promising solution. However, recycling causes mechanical and thermal shortcomings in polymers. Addition of nanoparticles to recycled materials may overcome these shortcomings. Nanocomposites can be achieved either by blending or through polymerization. Sepiolite as a nanoparticle enhances the thermal properties of polymers. In this study, the effect of sepiolite as a nanoparticle has been investigated on the thermal and mechanical behavior of recycled high-density polyethylene (HDPE). Hardness, density, Vicat softening temperature, melt flow rate (MFR), and differential scanning calorimetry has been investigated on recycled HDPE containing different amount of sepiolite. Results showed that both the amount of recycled HDPE and the sepiolite content affect the mechanical and thermal behavior of samples. Increasing the amount of recycled component resulted in increasing of MFR, a slight increase in density, and decrease in Vicat softening point, hardness, melting temperature, and degree of crystallization. As an opposite effect of these to factors on crystallinity of HDPE, sepiolite content has better effects to be considered separately for each recycle content. Sepiolite can be introduced as a low-cost reinforcement filler in recycling industry for tuning new compositions based on process condition, or vice versa.


2018 ◽  
Vol 06 (01n02) ◽  
pp. 1850002
Author(s):  
Ban M. Alshabander ◽  
Awattif A. Mohammed ◽  
Asmaa Sh. Khalil

In this study, coal ash/recycled plastic composite material was fabricated with post-consumer high-density polyethylene (HDPE) and coal ash particles. The main idea of using coal ash, since it is also a waste product, as reinforcing filler in recycled HDPE is to reduce the cost, develop lightweight and produce environmental-friendly materials. Coal ash/recycled plastic composite have been used in significant applications as construction materials including flooring, landscaping, fencing, railing window framing and roof tiles. Effect of coal ash loading on the mechanical properties and thermal conductivity of coal ash/recycled HDPE composite were determined. It is expected to use waste materials in new field by getting novel composite materials with developed mechanical properties. It was found that coal ash filler indicated significant improvement on the mechanical properties of composites. The results show that the impact decreased tremendously from 57.32 to 15.8[Formula: see text]kJ/m2 with only 30[Formula: see text]wt.% loading of coal ash. The filler increases the elasticity of the material and reduces its ability to absorb deformation energy.


2010 ◽  
Vol 93-94 ◽  
pp. 165-168 ◽  
Author(s):  
Jintamai Suwanprateeb ◽  
Kitiya Wasoontararat ◽  
Waraporn Suvannapruk

In this study, a combination of powder printing technique and two-stepped heat treatment was utilized as a mean to prepare porous high density polyethylene structure. Physical and mechanical properties of the resulting structure were then characterized by porosity measurement and monotonic tensile test. It was found that the relationship between structure and properties was strongly influenced by processing conditions including compositions, treatment times and treatment temperatures. This process could increase the properties of porous high density polyethylene significantly over the single-stepped heat treatment without destroying porous structure. Porous high density polyethylene bodies having a porosity ranging from 46-58 percents with tensile strength up to approximately 4 MPa could be successfully prepared in this study.


Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1361 ◽  
Author(s):  
David Manas ◽  
Miroslav Manas ◽  
Ales Mizera ◽  
Pavel Stoklasek ◽  
Jan Navratil ◽  
...  

This article discusses the possibilities of using radiation cross-linked high density polyethylene (HDPEx) acting as a filler in the original high density polyethylene (HDPE) matrix. The newly created composite is one of the possible answers to questions relating to the processing of radiation cross-linked thermoplastics. Radiation cross-linked networking is—nowadays, a commonly used technology that can significantly modify the properties of many types of thermoplastics. This paper describes the influence of the concentration of filler, in the form of grit or powder obtained by the grinding/milling of products/industrial waste from radiation cross-linked high density polyethylene (rHDPEx) on the mechanical and processing properties and the composite structure. It was determined that, by varying the concentration of the filler, it is possible to influence the mechanical behaviour of the composite. The mechanical properties of the new composite—measured at room temperature, are generally comparable or better than the same properties of the original thermoplastic. This creates very good assumptions for the effective and economically acceptable, processing of high density polyethylene (rHDPEx) waste. Its processability however, is limited; it can be processed by injection moulding up to 60 wt %.


2020 ◽  
Vol Volume 15 ◽  
pp. 3159-3169
Author(s):  
Yiben Huang ◽  
Bingqian Jiang ◽  
Xiaqi Miao ◽  
Jiedong Ma ◽  
Jianing Wang ◽  
...  

2012 ◽  
Vol 217-219 ◽  
pp. 603-608
Author(s):  
Xing Bo Shi ◽  
Ju Lin Wang ◽  
Xiao Ping Cai

The effect of low molecular weight (LMW) ethylene homoploymer on the structure and properties of bimodal high density polyethylene (HDPE) was studied by blending two commercial bimodal HDPE resins (tandem reactor) with two types of LWM ethylene homopolymer. The molecule weight and molecule weight distribution, crystsallinity, rheological and mechanical properties of composites were characterized by high temperature gel permeation chromatography (HT-GPC), differential scanning calorimetry (DSC), capillary rheometer respectively. For composites of bimodal HDPE and LMW ethylene homopolymer, the polydispersity index (PDI) and crystallinity can be effectively increased when reduce the molecular weight of first reactor in tandem reactor. The viscosity of composites decreases at high shear rate. Increasing of LMW component has a positive effect on processing properties and tensile strength, while makes composites brittle.


Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2408
Author(s):  
Anton Chepurnenko ◽  
Stepan Litvinov ◽  
Besarion Meskhi ◽  
Alexey Beskopylny

A theoretical solution of the problem of thick-walled shell optimization by varying the mechanical characteristics of the material over the thickness of the structure is proposed, taking into account its rheological properties. The optimization technique is considered by the example of a cylindrical shell made of high-density polyethylene with hydroxyapatite subjected to internal pressure. Radial heterogeneity can be created by centrifugation during the curing of the polymer mixed with the additive. The nonlinear Maxwell–Gurevich equation is used as the law describing polymer creep. The relationship of the change in the additive content along with the radius r, at which the structure is equally stressed following the four classical criteria of fracture, is determined in an elastic formulation. Moreover, it is shown that a cylinder with equal stress at the beginning of the creep process ceases to be equally stressed during creep. Finally, an algorithm for defining the relationship of the additive mass content on coordinate r, at which the structure is equally stressed at the end of the creep process, is proposed. The developed algorithm, implemented in the MATLAB software, allows modeling both equally stressed and equally strength structures.


2020 ◽  
Author(s):  
Congcong Ding ◽  
Yang Chen ◽  
Yumeng Shi ◽  
Minghui Li ◽  
Lihua Hu ◽  
...  

Abstract Background: Data on the relationship of nontraditional lipid profiles [total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio, triglyceride (TG)/HDL-C ratio, low-density lipoprotein cholesterol (LDL-C)/HDL-C ratio, non-high-density lipoprotein cholesterol (non-HDL-C)] with the risk of peripheral artery disease (PAD) are limited. The present study investigated the relationship of nontraditional lipid indices with PAD in hypertensive patients.Methods: This cross-sectional study was performed among 10,900 adults with hypertension. Participants were diagnosed with PAD when their ankle-brachial index (ABI) < 0.9. The association of nontraditional lipid profiles with PAD was examined using multivariate logistic regression analysis and the restricted cubic spline.Results: All nontraditional lipid indices were independently and positively associated with PAD in a dose-response fashion. After multivariable adjustment, the per SD increments of the TC/HDL-C, TG/HDL-C, LDL-C/HDL-C ratios and non-HDL-C were all significantly associated with 37%, 14%, 40%, and 24% higher risk for PAD, respectively. The adjusted ORs (95% CI) for PAD were 1.77 (1.31, 2.40), 1.71 (1.25, 2.34), 2.03 (1.50, 2.74), and 1.70 (1.25, 2.31) when comparing the highest tertile to the lowest tertile of the TC/HDL-C, TG/HDL-C, LDL-C/HDL-C ratios and non-HDL-C, respectively. Conclusions: Among Chinese hypertensive adults, all nontraditional lipid indices were positively associated with PAD, and the LDL-C/HDL-C and TC/HDL-C ratios were better for predicting PAD than other nontraditional lipid indices, which may improve the risk stratification of cardiovascular disease and dyslipidemia management. Trial registration: CHiCTR, ChiCTR1800017274. Registered 20 July 2018


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