Modulus Of High-density Polyethylene Research Articles

Rice husk ash: Economical and high-quality natural-based reinforcing filler for linear low-density and high-density polyethylene

Rice husk ash (RiHA) was employed as the bio-originated and inexpensive filler prepared from agricultural wastes for reinforcing high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). X-ray fluorescence (XRF) spectroscopy showed ∼80.82% for the silica content of RiHA as well as the values of other components present in this bio-based filler. The composites were obtained via melt mixing followed by the compression molding by the hot press forming. Characterization of the composites by FT-IR spectroscopy revealed that the filler has the sheer effects on the vibrational bands of the polymers. The usage of X-ray diffraction (XRD) analysis to investigate the d-spacing values and the crystallinity of the samples, exhibited the increase of d-spacing upon reinforcing the polymers with RiHA. The scanning electron microscopy (SEM) images showed an average size of 32 µm for the irregular RiHA particles which uniformly dispersed in the polymeric matrices. The energy dispersive X-ray (EDX) analysis displayed C, O, and Si as the main constituting elements of the composites and alternatively confirmed the well dispersion of the filler particles into the polymer matrices. The mechanical measurements showed the significant improvements in Young’s modulus, yield stress, and hardness results of the polymers after reinforcing with the rice husk ash. For example, Young’s modulus of HDPE was increased ∼15% after incorporating 7 wt.% of RiHA into this polymer. These mechanical properties of the polymers were increased upon increasing the RiHA content, while the parameter of elongation at break was decreased.

Extremely high reinforcement of high‐density polyethylene by low loading of unzipped multi‐wall carbon nanotubes

AbstractMulti‐wall carbon nanotubes (MWCNTs) are excellent potential reinforcements for composites due to their high‐mechanical properties. However, a high concentration of MWCNTs is required to reach a good reinforcement. The present study is aimed to show that using unzipped MWCNTs (uMWCNTs) results in an extraordinary enhancement of the mechanical properties of high‐density polyethylene (HDPE). Using 0.2% wt/wt of uMWCNTs as a filler increases the tensile strength and Young's modulus of HDPE by more than 100%. Transmission electron microscopy (TEM), X‐ray diffraction, Raman, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy (XPS), and differential scanning calorimeter (DSC) studies show that the structure and functionality of uMWCNTs and HDPE matrix preserve for their composites. The enhancement in the mechanical properties is mainly associated with an interfacial interaction between separate uMWCNTs sheets and HDPE matrix resulting in increasing the degree of crystallinity and decreasing the crystallite size. Our study provides a new way to fabricate high‐performance composite materials with a low concentration of carbon nanostructures.

Analysis of Nanomechanical Properties of Polyethylene Using Molecular Dynamics Simulation

The nanomechanical properties of polymers are sensitively affected by subtle differences in molecular structures. When the modulus of high-density polyethylene (HDPE) was measured with an atomic fo...

Realizing mechanically reinforced all-polyethylene material by dispersing UHMWPE via high-speed shear extrusion

Due to its extraordinary molecular weight feature (Mw > 106 g/mol), ultra high molecular weight polyethylene (UHMWPE) plays as an appropriate reinforcement for polyethylene. However, ultrahigh molecular weight also causes remarkably high melt viscosity, which hinders the solvent-free processing of UHMWPE. Here, we report a self-reinforcement all-polyethylene material, high density polyethylene (HDPE)/UHMWPE via a melt processing of high-speed shear extrusion. A critical reinforced content of UHMWPE, 0.1 wt%, has been discovered. After reaching such content, the tensile strength and Young's modulus of HDPE can be reinforced remarkably at 500 rpm. Thanks to the high shear, UHMWPE is uniformly dispersed and to form reinforcement network in the HDPE matrix. Interestingly, UHMWPE long chains enable the appearance of lamellae orientation and shish-kebab crystalline morphology in the injection molded parts, which are responsible for the mechanical reinforcement behavior observed. Our current work offers a convenient, solvent-free processing strategy to manufacture super polyolefin blends containing UHMWPE.

Stiff and Tough Conductive Composites Using Carbon Black-Filled Polyethylene

Stiff and tough conductive composites were manufactured using carbon black compounded with high and low density polyethylene, as well as linear low density polyethylene. A low percolation threshold value for the composites was achieved at 2 wt% carbon black. The impact strengths of the composites incorporating low density and linear low density polyethylene were found to be almost 16 and 26 times greater, respectively, than that of high density polyethylene composites. On the other hand, the modulus of high density polyethylene filled with carbon black was 2 times as high as low and linear low density polyethylene-based composites. Tensile modulus increased with the content of carbon black, however the impact strength of the composites decreased.

Modeling the elastic modulus of HDPE in terms of stress-dependent thermally activated rate process

If a three-element mechanical model incorporating a stress-dependent thermally activated rate process is used to predict the instantaneous and anelastic components of elastic modulus of high density polyethylene, it is suggested that the measured elastic modulus determines the anelastic response rather than an instantaneous response and, furthermore, it is related to an interlamellar shear rather than a slip process in the crystalline region.

A crystalline ethylene, acenaphthylene, n‐hexene‐1 terpolymer exhibiting both high modulus and high elongation

AbstractPolyolefins are generally known either as partially crystalline thermoplastics or as elastomers. With the finding in the ethylene‐acenaphthylene copolymer system of the unusual properties of high crystallinity, high modulus, and no independent beta thermomechanical transition at high comonomer contents, it appeared that it might be possible to prepare a block polymer system which would retain the desirable low temperature transition near −110°C and “hard” acenaphthylene copolymer segments as well. Attempts were made, and the resulting terpolymer is described. An intermediate crystallinity polymer of apparently broad composition distribution was obtained with the modulus of high density polyethylene but the elongational characteristics of low density polyethylene.