Measurement and Analysis on Dynamics Cold Crystallization Parameter of High-Density Polyethylene (HDPE) Sheet by Vibration Force Field

2011 ◽  
Vol 103 ◽  
pp. 447-451
Author(s):  
Bing Li ◽  
Xue Mei Qin ◽  
Bao Shan Shi

Physics mechanics properties of polymer materials don’t only depend on their chemical constitution, molecular weight and distribution of molecular weight, but also depend on their agglomerate configuration. The effect of vibration on the microstructure and mechanical properties of high-density polyethylene (HDPE) sheets, obtained through vibration plasticating extruder in low temperature, were studied systematically. Crystalline polymer is analyzed by differential scanning calorimetry(DSC), wide angle X ray diffraction(WAXD). The test result which represents parameters of crystalline structure is helped to judge the outside factors for crystalline structure, such as melting point, crystallinity and heat of fusion by DSC and crystallinity, crystal plane distance and grain size by WAXD, and canning electron microcopy (SEM). The results indicate that the vibration extrudate in low temperature has higher crystallinity, perfect crystallite, and strong inter-spherulite ties.

2011 ◽  
Vol 291-294 ◽  
pp. 561-564
Author(s):  
Bao Shan Shi ◽  
Xue Mei Qin ◽  
Bing Li

By the apparatus of differential scanning calorimetry (DSC), scanning electron microcopy (SEM) and wide angle X-ray diffraction (WAXD), The effect of vibration on the microstructure and mechanical properties of high-density polyethylene (HDPE) sheets, obtained through vibration plasticating extruder in low temperature, were measured and analysed. The result show that the tensile strength was much improved under the reciprocating axial vibration in low temperature. The phenomenon indicate that the vibration extrudate in low temperature has higher crystallinity, perfect crystallite, and strong inter-spherulite ties, which account for enhancement of the mechanical properties of sheets, compared to conventional static extrusion.


2011 ◽  
Vol 337 ◽  
pp. 368-371
Author(s):  
Xue Mei Qin ◽  
Bao Shan Shi ◽  
Bing Li

The effect of vibration on the microstructure and mechanical properties of high-density polyethylene (HDPE) sheets, obtained through vibration plasticating extruder in low temperature, were studied systematically. Property Tests show that the tensile strength and the Vika temperature were much improved under the reciprocating axial vibration in low temperature. Differential scanning calorimetry , scanning electron microcopy and wide angle X-ray diffraction were executed to analyze the microstructure of the samples. The results indicate that the vibration extrudate in low temperature has higher crystallinity, perfect crystallite, and new crystal morphology formed , which account for enhancement of the mechanical properties and Vika temperature of sheets, compared to conventional static extrudate.


2005 ◽  
Vol 59 (9) ◽  
pp. 1148-1154 ◽  
Author(s):  
Spiros Tzavalas ◽  
Vasilis G. Gregoriou

High-density polyethylene (HDPE)–clay nanocomposites have been prepared using the melt intercalation technique. Organically modified montmorillonite at various loadings (0.5–7%) was used as a nanoadditive. Fourier transform infrared spectroscopy (FT-IR) was utilized for the first time to monitor the stress-induced crystal-to-crystal transformations of the polyethylene matrix with respect to the clay loading as well as to the degree of mechanical strain. In addition, polarized infrared measurements revealed information on both the orientation and the stress-induced distortion of the crystals. It was concluded that the crystal-to-crystal transformations are hindered by the presence of the clay, which also prevented the crystals from orienting even at low clay loadings (1%). Finally, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) measurements confirmed the presence of the stress-induced crystalline structures in agreement with the infrared measurements.


2014 ◽  
Vol 34 (9) ◽  
pp. 813-821 ◽  
Author(s):  
Gaurav Madhu ◽  
Haripada Bhunia ◽  
Pramod K. Bajpai ◽  
Veena Chaudhary

Abstract Polyblend films were prepared from high-density polyethylene (HDPE) and poly(l-lactic acid) (PLLA) up to 20% PLLA by the melt blending method in an extrusion mixer with post-extrusion blown film attachment. The 80/20 (HDPE/PLLA) blend was compatibilized with maleic anhydride grafted polyethylene (PE-g-MA) in varying ratios [up to 8 parts per hundred of resin (phr)]. Tensile properties of the films were evaluated to obtain optimized composition for packaging applications of both non-compatibilized and compatibilized blends. The compositions HDPE80 (80% HDPE and 20% PLLA) and HD80C4 (80% HDPE, 20% PLLA and 4 phr compatibilizer) were found to be optimum for packaging applications. However, better tensile strength (at yield) and elongation (at break) of 80/20 (HDPE/PLLA) blend were noticed in the presence of PE-g-MA. Further, thermal properties and morphologies of these blends were evaluated. Differential scanning calorimetry (DSC) study revealed that blending does not much affect the crystalline melting point of HDPE and PLLA, but heat of fusion of 80/20 (HDPE/PLLA) blend was decreased as compared to that of neat HDPE. Spectroscopy studies showed evidence of the introduction of some new groups in the blends and gaining compatibility in the presence of PE-g-MA. The compatibilizer influenced the morphology of the blends, as apparent from scanning electron microscopy (SEM) and supported by Fourier transform infrared (FTIR).


2017 ◽  
Vol 51 (28) ◽  
pp. 3923-3929 ◽  
Author(s):  
Fatemeh Ahangaran ◽  
Ali Hassanzadeh ◽  
Sirous Nouri ◽  
Rasoul Esmaeely Neisiany

High-density polyethylene nanocomposites containing Fe3O4 nanoparticles were prepared by employing melt mixing process. The amorphous Fe3O4 nanoparticles with average size about 50 nm were prepared by the conventional coprecipitation method from iron (ΙΙ and ΙΙΙ). Thermal and dielectric properties of high-density polyethylene and its nanocomposites were investigated via differential scanning calorimetry and electrochemical impedance spectroscopy. The crystalline structure of high-density polyethylene and Fe3O4/high-density polyethylene nanocomposite were studied by wide-angle X-ray diffraction, which confirmed orthorhombic crystalline structure. The results of thermal and dielectric analysis indicated that the addition of Fe3O4 nanoparticles to high-density polyethylene matrix leads to decreasing degree of crystallinity and improvement of dielectric constant.


2018 ◽  
Vol 5 (7) ◽  
pp. 180394 ◽  
Author(s):  
Weijun Miao ◽  
Hao Zhu ◽  
Tianchen Duan ◽  
Hongbing Chen ◽  
Feng Wu ◽  
...  

High-density polyethylene (HDPE)/ultra-high-molecular-weight polyethylene (UHMWPE) fibre composites were prepared via solution crystallization to investigate the components of epitaxial crystal growth on a highly oriented substrate. Scanning electron microscopy morphologies of HDPE crystals on UHMWPE fibres revealed that the edge-on ribbon pattern crystals that were formed initially on UHMWPE fibres converted afterwards to a sheet shape as crystallization progressed. Wide-angle X-ray diffraction confirmed that the polymer chain oriented along the fibre axis and the orthorhombic crystal form of HDPE remained unchanged in HDPE/UHMWPE fibre composite systems. The thermal behaviour of the fibre composites measured by differential scanning calorimetry showed double melting peaks, the nature of which, as disclosed by partial melting experiments, is ascribed to bilayer components existing in the induced crystals: the inner layer is composed of more regularly folded chain crystals induced by UHMWPE fibres, and the outer layer formed on the inner one with a thinner and lower ordered crystal structure.


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.


2017 ◽  
Vol 36 (4) ◽  
pp. 167-182 ◽  
Author(s):  
Hongfu Zhou ◽  
Zhanjia Wang ◽  
Guozhi Xu ◽  
Xiangdong Wang ◽  
Bianying Wen ◽  
...  

Different content of dicumyl peroxide (DCP) acting as a crosslinking agent was mixed with high-density polyethylene (HDPE) in a Haake internal mixer to improve the viscoelasticity and foamability of HDPE. The crosslinked HDPE samples were foamed in a high pressure stainless steel autoclave using CO2 as the physical blowing agent. The molecular weight, crystallization behavior and rheological properties of various HDPE samples were examined by gel permeation chromatography, differential scanning calorimetry, rotational rheometer, and torque rheometer, respectively. The foaming properties of various samples were characterized by scanning electron microscope and densimeter. It was found that with the increasing content of DCP, the molecular weight, crystallization temperature, complex viscosity, and storage modulus of HDPE increased and the crystallization degree of HDPE decreased. When 0.2 phr of DCP was introduced into HDPE, the expansion volume ratio of HDPE showed the highest value, which could be more than 7 times.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4024
Author(s):  
Piotr Olesik ◽  
Marcin Godzierz ◽  
Mateusz Kozioł ◽  
Jakub Jała ◽  
Urszula Szeluga ◽  
...  

In this paper, we investigated theimpact of glassy carbon (GC) reinforcement oncrystal structure and the mechanical performance of high-density polyethylene (HDPE). We made composite samples by mixing HDPE granules with powder in ethanol followed bymelt mixing in a laboratory extruder. Along with the investigated composite, we also prepared samples with carbon nanotubes (CNT), graphene (GNP) and graphite (Gr) to compare GC impact with already used carbon fillers. To evaluate crystal structure and crystallinity, we used X-ray diffraction (XRD) and differential scanning calorimetry (DSC). We supported the XRD results with a residual stress analysis (RSA) according to the EN15305 standard. Analysis showed that reinforcing with GC leads to significant crystallite size reduction and low residual stress values. We evaluated the mechanical properties of composites with hardness and tensile testing. The addition of glassy carbon results inincreased mechanical strength incomposites with CNT and GNP.


Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1874
Author(s):  
Enrique Blázquez-Blázquez ◽  
Ernesto Pérez ◽  
Vicente Lorenzo ◽  
María L. Cerrada

Blends of poly(ε-caprolactone) (PCL) and high-density polyethylene (HDPE) have been prepared at different compositions in order to assess the effect of HDPE on gas transport and mechanical behaviors of PCL. Previous to this evaluation, a complete morphological, structural, and thermal characterization were performed using techniques, including SEM, contact angle, FTIR, differential scanning calorimetry, and X-ray diffraction with synchrotron radiation at small and wide angles. Low HDPE incorporations allow interactions to be established at interfaces in the amorphous regions and the enhancement of the mechanical performance. Consequently, the addition of a small amount of HDPE (ranging from 5 to 10 wt%) appears to be appropriate in certain bio-applications where a higher mechanical behavior is required.


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