Tuning of HDPE Properties for 3D Printing

2018 ◽  
Vol 773 ◽  
pp. 67-71 ◽  
Author(s):  
Paweesinee Chatkunakasem ◽  
Panisa Luangjuntawong ◽  
Aphiwat Pongwisuthiruchte ◽  
Chuanchom Aumnate ◽  
Pranut Potiyaraj

The objective of this study is to improve high density polyethylene (HDPE) properties for 3D printing by addition of graphene and low density polyethylene (LDPE). Graphene was prepared by modified Hummer’s method. The prepared graphene was characterized by the infrared spectroscopy and the X-ray diffraction analysis (XRD). Graphene/HDPE and LDPE/HDPE composites were successfully prepared through the melt-blending technique using a twin-screw extruder. The melt flow index (MFI) and differential scanning calorimetry (DSC) were employed to characterize neat HDPE and the modified HDPE. FTIR and XRD results show that graphite was successfully changed into graphene completely and MFI of graphene/HDPE and LDPE/HDPE decreased as the amount of graphene and LDPE in the composite blends increased. DSC results show that the addition of low crystalline polymers can reduce a crystallization temperature and crystallinity content.

2014 ◽  
Vol 1033-1034 ◽  
pp. 869-872
Author(s):  
Kun Yan Wang

Polypropylene (PP)/ethylene-vinyl acetate (EVA) blends were prepared using a twin-screw extruder by melt blending method. The influences of the EVA contents in PP/EVA blends on crystallization behavior and mechanical properties were investigated by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). XRD results show that the EVA not change the crystal structure in the blends but only decrease the intensity of the diffraction peak. DSC results showed that the melting point and crystallization point decreased when EVA added to the blend. The tensile properties of PP/EVA blend become much better.


Materials ◽  
2005 ◽  
Author(s):  
Han-Xiong Huang ◽  
Guo Jiang ◽  
Shan-Qiang Mao

Polypropylene (PP)/nano-calcium carbonate (nano-CaCO3) composite was prepared using a co-rotating, intermeshing twin-screw extruder. The effect of flow fields on the morphology of the nanocomposite was investigated. Transmission electron microscopy (TEM) was used for the determination of the morphology in the nanocomposite. The crystallization behavior of the nanocomposite was studied by using differential scanning calorimetry (DSC) and the melt shear viscosity was investigated by a melt flow index tester. The study showed that the flow field, through appropriately combining the type of the screw elements in this work, plays an important role in developing morphology of the nanocomposite. In addition, it was shown that the melt viscosity for the nanocomposite at the filler content less than 10 wt% is lower than that of neat PP.


2005 ◽  
Vol 13 (4) ◽  
pp. 385-394
Author(s):  
Huiyu Bai ◽  
Yong Zhang ◽  
Yinxi Zhang ◽  
Xiangfu Zhang ◽  
Wen Zhou

New toughened poly(butylene terephthalate) (PBT)/bisphenol A polycarbonate (PC) blends were obtained by melt blending with commercial poly(ethylene-co-octene) copolymer (POE), varying the POE content up to 10 wt%, in a twin screw extruder, followed by injection moulding. The influence of POE on the properties of the PBT/PC blends was investigated in terms of mechanical testing, dynamic mechanical thermal (DMTA) analysis, differential scanning calorimetry (DSC), and scanning electronic microscopy (SEM). The results showed that addition of POE led to remarkable increases in the impact strength, elongation at break and Vicat temperature, and a reduction in the tensile strength and flexural properties of PBT/PC blends. The morphology of the blends was observed using SEM and the average diameter of the dispersed phase was determined by image analysis. The critical inter-particle distance for PBT/PC was determined.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
B. Zazoum ◽  
E. David ◽  
A. D. Ngô

PE/clay nanocomposites were prepared by mixing a commercially available premixed polyethylene/O-MMT masterbatch into a polyethylene blend matrix containing 80 wt% low-density polyethylene and 20 wt% high-density polyethylene with and without anhydride modified polyethylene (PE-MA) as the compatibilizer using a corotating twin-screw extruder. In this study, the effect of nanoclay and compatibilizer on the structure and dielectric response of PE/clay nanocomposites has been investigated. The microstructure of PE/clay nanocomposites was characterized using wide-angle X-ray diffraction (WAXD) and a scanning electron microscope (SEM). Thermal properties were examined using differential scanning calorimetry (DSC). The dielectric response of neat PE was compared with that of PE/clay nanocomposite with and without the compatibilizer. The XRD and SEM results showed that the PE/O-MMT nanocomposite with the PE-MA compatibilizer was better dispersed. In the nanocomposite materials, two relaxation modes are detected in the dielectric losses. The first relaxation is due to a Maxwell-Wagner-Sillars interfacial polarization, and the second relaxation can be related to dipolar polarization. A relationship between the degree of dispersion and the relaxation ratefmaxof Maxwell-Wagner-Sillars was found and discussed.


Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2912 ◽  
Author(s):  
Mateusz Galeja ◽  
Klaudiusz Wypiór ◽  
Jan Wachowicz ◽  
Przemysław Kędzierski ◽  
Aleksander Hejna ◽  
...  

Polyoxymethylene (POM) is one of the most popular thermoplastic polymers used in the industry. Therefore, the interest in its potential applications in rapid prototyping is understandable. Nevertheless, its low dimensional stability causes the warping of 3D prints, limiting its applications. This research aimed to evaluate the effects of POM modification with ethylene-vinyl acetate (EVA) (2.5, 5.0, and 7.5 wt.%) on its processing (by melt flow index), structure (by X-ray microcomputed tomography), and properties (by static tensile tests, surface resistance, contact angle measurements, differential scanning calorimetry, and thermogravimetric analysis), as well as very rarely analyzed emissions of volatile organic compounds (VOCs) (by headspace analysis). Performed modifications decreased stiffness and strength of the material, simultaneously enhancing its ductility, which simultaneously increased the toughness even by more than 50% for 7.5 wt.% EVA loading. Such an effect was related to an improved linear flow rate resulting in a lack of defects inside the samples. The decrease of the melting temperature and the slight increase of thermal stability after the addition of EVA broadened the processing window for 3D printing. The 3D printing trials on two different printers showed that the addition of EVA copolymer increased the possibility of a successful print without defects, giving space for further development.


2011 ◽  
Vol 311-313 ◽  
pp. 20-25
Author(s):  
Jian Peng ◽  
You Ming Cao

The composites composed of polyamide66(PA66), polypropylene(PP), and magnesium oxysulfate whisker(MOS) were prepared by means of melt blending through co-rotation twin screw extruder. The standard samples were prepared by injection machine. The effect of coupling agents on the whisker surface, and the influence of MOS content on mechanical properties, heat properties, flame-retardant properties and the microstructure of the composites were investigated by scanning electron microscopy(SEM), thermogravimetry(TG) and differential scanning calorimetry(DSC) techniques, respectively. The results showed that the MOS whisker modified with coupling agents KH570 possesses better activation exponential and dispersity, and the tensile strength, flexural strength and toughness of PA66/PP/MOS composite were firstly increased and then decreased with the MOS content increasing, the optimum adding amount of MOS was 25phr. The flame retardant property was improved remarkable by adding of MOS.


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1159
Author(s):  
Ana Ibáñez-García ◽  
Asunción Martínez-García ◽  
Santiago Ferrándiz-Bou

This article is focused on studying the effect of the reprocessing cycles on the mechanical, thermal, and aesthetic properties of a biocomposite. This process is based on starch thermoplastic polymer (TPS) filled with 20 wt% almond shell powder (ASP) and epoxidized linseed oil (ELO) as a compatibilizing additive. To do so, the biocomposite was prepared in a twin-screw extruder, molded by injection, and characterized in terms of its mechanical, thermal, and visual properties (according to CieLab) and the melt flow index (MFI). The analyses carried out were tensile, flexural, Charpy impact tests, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA). The effects of the reprocessing were also studied for the biodegradable unfilled TPS polymer. The results showed that TPS and TPS/ASP biocomposite suffer changes progressively on the properties studied after each reprocessing cycle. Furthermore, it was observed that the addition of ASP intensified these effects regarding TPS. However, in spite of the progressive degradation in both cases, it is technically feasible to reprocess the material at least three times without needing to incorporate virgin material.


2012 ◽  
Vol 488-489 ◽  
pp. 473-477 ◽  
Author(s):  
Onusa Saravari ◽  
Kodchagorn Keeratichiraththitikan ◽  
Noppadon Kerddonfag ◽  
Wannee Chinsirikul

This study investigated the effect of the organic phthalocyanine blue and inorganic ultramarine blue pigments on nucleation of polypropylene (PP). The PP/pigment pellets containing various concentrations of each pigment (0.0001-0.1 wt %) were prepared by a melt blending process using a single-screw extruder, followed by fabricating into thin sheets using a single-screw plastic sheet extruder. The nucleation effects of both pigments were characterized by wide angle X-ray diffraction (WAXD), and differential scanning calorimetry (DSC) techniques. The WAXD patterns revealed that the addition of phthalocyanine blue or ultramarine blue did not affect the crystal structure of PP. The DSC results indicated that both pigments were able to nucleate PP, where the organic phthalocyanine blue pigment was a very efficient nucleating agent, increasing the crystallization temperature of PP by 15oC. The results of tensile and optical tests showed that the tensile strength and clarity of PP were improved with phathalocyanine blue addition.


2011 ◽  
Vol 194-196 ◽  
pp. 2347-2350 ◽  
Author(s):  
Zi Nian Zhao ◽  
Xin Xin Nie ◽  
Rui Wang

By means of melt blending process in a co-rotating twin screw extruder with two-step process, the low density polyethylene (LDPE)/ethylene octene copolymer (POE)/zeolite molecular sieves (ZMS) composites were prepared. The influence of ZMS on the crystallinity, mechanical properties and permeability was investigated by differential scanning calorimetry(DSC), universal testing machine and permeability tester, respectively. The results showed that the addition of ZMS made the crystallinity of composite film decreased and the growth rate of crystal nucleus promoted. As the content of ZMS rose, the mechanical properties of composite film decreased, while the CO2, O2permeability and the moisture permeability increased.


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