For extensive radiation exposure, inventing a novel radiation shielding material is a burning issue at present for the purpose of life saving. Considering this thought, in this study, by adding ...sundry amounts of Bi2O3 into pure high-density polyethylene (HDPE), six HDPE systems were prepared to evaluate the radiation shielding efficiency. These HDPE systems were HDPEBi-0 (pure HDPE), HDPEBi-10 (10 wt% Bi2O3), HDPEBi-20 (20 wt% Bi2O3−), HDPEBi-30 (30 wt% Bi2O3), HDPEBi-40 (40 wt% Bi2O3), and HDPEBi-50 (50 wt% Bi2O3). The values of the linear attenuation coefficients of the experimental results (calculated in the lab using HPGe) were compared with the theoretical results (obtained using Phy-X software) at 0.060, 0.662, 1.173, and 1.333 MeV energies. To ensure the accurateness of the experimental results, this comparison was made. It was crystal clear that for energy values from 0.06 MeV to 1.333 MeV, all the experimental values were in line with Phy-X software data, which demonstrated the research setup’s reliability. Here, the linear attenuation coefficient (LAC), and mean free path (MFP) shielding parameters were assessed. At the energy of 1.333 MeV, sample HDPEBi-0 showed an HVL value 1.7 times greater than that of HDPEBi-50, yet it was 23 times greater at 0.0595 MeV. That means that for proper radiation protection, very-low-energy HDPE systems containing 10–50% Bi2O3 could be used; however, the thickness of the HDPE system must be increased according to the energy of incident radiation.
A hydrocarbon fuel extracted from waste high-density polyethylene (WHDPE) by catalytic pyrolysis in a batch scale reactor is blended with diesel by 30% vol. (called as D70H30) is tested in a variable ...compression ratio engine equipped with a common rail system. Experiments were conducted at three compression ratios (16:1, 17.5:1, and 19:1) and exhaust gas re-circulation (EGR) rates (0%, 10%, and 20%) at the engine’s rated power to evaluate its combustion, performance and emission characteristics. The results revealed that, increasing the compression ratio resulted in higher peak cylinder pressure (PCP) and heat release rates (HRR). Introduction of EGR diminished both PCP and HRR peaks. The brake thermal efficiency of D70H30 blend was 4% lower than diesel at same operating conditions which got better at higher compression ratio without EGR. NOx emission was highest when injected at compression ratio 19:1 and at 0% EGR rate which was 6% and 3% higher than diesel and D70H30 blend operated at engine stock settings. In comparison with baseline diesel smoke opacity remained lower at all operating conditions, where lowest smoke emission was recorded at CR19 and at 0% EGR rate. UHC and CO emission followed the similar trend of smoke opacity. Whereas CO2 emission increased with compression ratio and reduced with induction of EGR. It can be concluded from the study that at higher compression ratio and low EGR rates D70H30 blend can be effectively utilized in a CRDi engine.
Corn stalk (CS) was used as raw material to prepare biochar. Corn stalk biochar /HDPE composite (CSB/HDPE) was prepared by extrusion method with 3 wt% MA added. The effect of corn stalk biochar (CSB) ...on the rheological properties of HDPE under different conditions was studied. The interface performance of each component with HDPE was studied by using the Harmonic‐Mean interface equation. The purpose is to provide guidance for the processing and molding of materials by studying the rheological properties and interface properties of the materials. The results showed that, compared with CS, the interfacial tension between CSB and HDPE was lower; Research on dynamic rheological properties showed that an appropriate amount of CSB can improve the processing performance of HDPE; With the increase of CSB content, the stability of the composite system decreased, but the elasticity and viscosity increased correspondingly. The steady‐state rheological properties showed that shear induced compatibility occurs in the composite system at high shear rates; Compared with HDPE, 50 %CSB/HDPE was more sensitive to temperature and had higher viscous flow activation energy. In addition, the tensile strength and flexural strength of the composite material reached the maximum when the CSB content was 50 %, which were 28.69 MPa and 30.14 MPa, respectively. Overall, the study of rheological properties of materials provides guidance for the application of CSB in polymers and broadens the way of waste resources utilization.
In this paper, the rheological and interfacial properties of CSB/HDPE composites were studied in detail, and the interaction between filler and matrix was discussed. This study provides guidance for the more effective use of filler and is of great significance in the field of composite processing.
High-density polyethylene (HDPE) conductive polymer composites are prepared using carbon fillers, such as natural flake graphite (FG), carbon black (CB), and carbon fibre (CF). Here, micro-sized FG ...as the main conductive filler, nano-sized CB as assistant conductive filler, and short CF as flexibility-enhanced materials are internally mixed with HDPE in a certain weight ratio. Commercial conductive polymer composite is prepared by hot pressing technology. Two kinds of conductive composites are selected by optimising the ratio of carbon fillers and HDPE. CF
4%
(CB + FG)
1:5
HDPE
27%
composite has the higher volume conductivity of 20.76 S cm
−1
with a bending strength of 39.5 MPa. CF
4%
(CB + FG)
1:4
HDPE
30%
composite has the larger bending strength of 53.6 MPa with a volume conductivity of 18.82 S cm
−1
. The electrochemical corrosion resistances of those two composite electrodes are investigated over 900 charging/discharging cycles in the lead methanesulfonate flow cell. CF
4%
(CB + FG)
1:4
HDPE
30%
composite exhibits better durability than CF
4%
(CB + FG)
1:5
HDPE
27%
composite.
In this study, a biodegradable, cheap and durable recycled high-density polyethylene (rHDPE) polymer reinforced with rice husk (RH) fibre was fabricated into a foam structure through several ...processes, including extrusion, internal mixing and hot pressing. The effect of filler loading on the properties of the foam and the influence of RH surface treatments on the filler-matrix adhesion and mechanical properties of the composite foam were investigated. The morphological examination shows that 50 wt.% filler content resulted in an effective dispersion of cells with the smallest cell size (58.3 µm) and the highest density (7.62 × 1011 sel/cm
). This small cell size benefits the mechanical properties. Results indicate that the tensile strength and the Young's modulus of the alkali-treated RH/rHDPE composite foam are the highest amongst the treatments (10.83 MPa and 858 MPa, respectively), followed by UV/O
, which has shown considerable increments compared with the untreated composite. The flexural and impact tests also show the increment in strength for the composite foam after chemical treatment. Although the UV/O
surface treatment has minor influence on the mechanical enhancement of the composite foam, this method may be a reliable surface treatment of the fibre-reinforced composite.
The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process LOGIFRUIT (EU register number RECYC260). The input consists of pre‐washed ...high‐density polyethylene (HDPE) or polypropylene (PP) crates from closed and controlled food distribution loops. The process separates crates by material type. Crates are ground to flakes, possibly extruded to pellets and used by companies approved to be in the loop to manufacture new crates. The Panel considered that the quality management system (QAS) put in place to ensure compliance of the origin of the input with Commission Regulation (EC) No 282/2008 and to provide full traceability is critical. The Panel concluded that, when run under the conditions described, the input of the process LOGIFRUIT exclusively originates from product loops which are in closed and controlled chains. The process is designed to ensure that only crates intended for food contact are used and that contamination other than by food can be ruled out. Therefore, the recycling process LOGIFRUIT to produce HDPE and PP crates to be used in contact with fruits and vegetables, and packed meat and fish, dairy, bakery and pastry products is not of safety concern.
In this paper, we developed a mathematical modeling to represent the damage of thermoplastic pipes. On the one hand, we adapted the theories of the rupture pressure to fit the High Density ...Polyethylene (HDPE) case. Indeed, the theories for calculating the rupture pressure are multiple, designed originally for steels and alloys. For polymer materials, we have found that these theories can be adapted using a coefficient related to the nature of the studied material. The HDPE is characterized by two important values of pressure, deduced from the ductile form of the internal pressures evolution until burst. For this reason, we have designed an alpha coefficient taking into account these two pressures and giving a good approximation of the evolution of the experimental burst pressures through the theoretically corrected ones, using Faupel㒒s pressure formula. Then, we can deduce the evolution of the theoretical damage using the calculated pressures. On the other hand, two other mathematical models were undertaken. The first one has given rise to an adaptive model referring to an expression of the pressure as a function of the life fraction, the characteristic pressures and the critical life fraction. The second model represents a continuum damage model incorporating the pressure equations as a function of the life fraction and based on the burst pressure s static damage model. These models represent important tools for industrials to assess the failure of thermoplastic pipes and proceed quick checks
Blending of polyamide 6/high density polyethylene (PA6/HDPE=70/30 wt%) was prepared by melt compounding using a twin screw extruder followed by injection molding using HDPE-g-MAH served as ...compatibilizer. A series combination of PA6/HDPE with HDPE-g-MAH were blended with varied composition of 100/0, 98/2, 96/4, 94/6 and 92/8. The mechanical properties of the samples such as tensile test, flexural test and elongation at break were measured by universal tensile machine while hardness was measured using the Zwick Roell hardness tester. The composites were characterized by Fourier Transform Infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and Thermogravimetric Analyzer (TGA). The addition of HDPE-g-MAH (2wt%) showed increased in modulus, strength and hardness but elongation at break decreased. DSC tests showed similar trend for all compositions. All mechanical tests also showed that composition of 98% PA6/HDPE with 2% HDPE-g-MAH has the highest value indicated best formulation for this research.
With a significant number of features (namely being multipurpose, inexpensive and durable), thermoplastic polymers, most often named plastics, are part of our daily routine, with an increasing ...production over the last decade. Among them, polyethylene terephthalate (PET), high-density polyethylene (HDPE) and polypropylene (PP) are distinguished as the five most commonly used plastics in various fields, mainly in the packaging industry. Even if it is difficult to imagine the world without plastics, the boosted plastic assembly comes with huge plastic waste, creating a number of challenges, as the most important threat for our environment, but also opportunities for recycling. Currently, a special attention is dedicated on how to improve the current recycling methods or to find new ones, since the quality of recycled plastics and potential chemical or biological contaminations are two problematic aspects. Understanding the properties of each thermoplastic polymer and the interaction with possible contaminants may be the key for an efficient recycling process. The aim of this paper was to evaluate the surface behaviour of different composite supports based on recycled PET before and after interaction with collagen (used as a biological contaminant). The surface contamination bias of PET supports was studied through different techniques: scanning electron microscopy (SEM), water uptake through swelling studies, contact angle measurements and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR).
•The impact strength of PP/HDPE blends was highly improved by gamma irradiation.•Gamma irradiated PP/HDPE blends had a better compatibility than that of un-irradiated ones.•The gamma radiation ...process made the chemical reaction between the PP and HDPE molecules.
Polypropylene (PP) blends with the other polymer, like polyethylene (PE), is normally used as for improving PP impact strength. In this paper, we wanted to improve the PP/high density polyethylene (HDPE) impact strength by increasing the compatibility of PP/HDPE with gamma irradiation process that the un-irradiated ones were also used for comparison. It was obvious that the impact strength increased when the HDPE (10 phr) was added into the PP matrix, compared with neat PP. Meanwhile, the irradiated ones had higher impact strength than that of un-irradiated PP/HDPE blends. This was contributed to the finer compatibility in γ-irradiated PP/HDPE blends, seen from the SEM. Furthermore, the FTIR data also confirmed that the 1,4-butanediol diacrylate (BDDA) was grafted on the backbone of PP/HDPE blends by γ radiation. It speculated that this correlated with the compatibilization improvement in γ-irradiated PP/HDPE blends. Finally, the possible mechanism after γ-irradiation was also proposed in this paper.
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