scholarly journals Mechanical properties and molecular structures of virgin and recycled HDPE polymers used in gravity sewer systems

2015 ◽  
Vol 46 ◽  
pp. 1-8 ◽  
Author(s):  
Mathias Alzerreca ◽  
Michael Paris ◽  
Olivier Boyron ◽  
Dominique Orditz ◽  
Guy Louarn ◽  
...  
2019 ◽  
Vol 10 (8) ◽  
pp. 1725
Author(s):  
Raffaella Aversa ◽  
Relly Victoria Virgil Petrescu ◽  
Antonio Apicella ◽  
Florian Ion Tiberiu Petrescu

A method for PET mechanical properties enhancement by reactive blending with HBA/HNA Liquid Crystalline Polymers for in situ highly fibrillar composites preparation is presented. LCP/PET blends were reactively extruded in presence of Pyromellitic Di-Anhydride (PMDA) and then characterized by Differential Scanning Calorimetry, Thermally Stimulated Currents and tensile mechanical properties. Moderate amounts of LCP in the PET (0.5 and 5%) and small amounts of thermo-active and reactive compatibilizer in the blend (0.3%) were found to significantly improve LCP melt dispersion, melts shear transfer and LCP fibril formation and adhesion. An unexpected improvement was probably due to the presence of two distinct phases’ supra-molecular structures involving PET-LCP and PMDA.


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.


Polyurethanes ◽  
2016 ◽  
Vol 1 (1) ◽  
Author(s):  
P. Ross ◽  
G. Sevilla ◽  
J. Quagliano

AbstractPolyurethane formulations utilized as liners for composite propellants were prepared by the reaction of toluene-2,4-diisocyanate (TDI) and isophorone diisocyanate (IPDI) with hydroxyl terminated polybutadiene (HTPB), while polymer chains were further extended with neopentyl glycol diol, NPG triol and two different triols (monoglyceryl ricinoleate, MRG and trimethylolpropane, TMP). Liners were formulated with micronized titanium dioxide mechanically dispersed in hydroxyl-terminated polybutadiene (HTPB). The molecular structures of liners were confirmed by FT-IR. Thermal properties indicated that the nature of chain extender (crosslinker) only slightly affected the temperatures for decomposition of liners. Two main thermal changes were found at 370∘C and another at around 440–500∘C, depending on the chain extender utilized. On the other side, mechanical properties varied within the range of 0,7-1,8 MPa, consistent with this kind of elastomers. Tensile strength at break was only significantly affected with TMP and MRG-chain extended liners at the lowest concentrations tested of 1,3 and 2% (w/w), respectively. However, the behaviour depended on whether TDI or IPDI isocyanate was utilized for curing. TMP 1,3% crosslinked liner cured with TDI had a tensile strength of 1,82MPa whileMRG-crosslinked liner cured with IPDI had a tensile strength of 1,56 MPa. It was observed that at the higher NCO/OH ratios essayed, tensile strength and hardness increased, improving mechanical properties. Our results confirmed that TMP and MRG triols together with NPG diols can be used to tailor mechanical and thermal properties of liners, considering their different hydroxyl functionalities and chain lengths.


2018 ◽  
Vol 25 (5) ◽  
pp. 891-901 ◽  
Author(s):  
Lijun Wang ◽  
Jianhui Qiu ◽  
Eiichi Sakai

AbstractIn this work, the rolling process was employed to fabricate polylactic acid/multi-walled carbon nanotube (PLA/MWCNT) composites at room temperature. The effects of the rolling conditions on the mechanical and electrical properties of the fabricated composites were investigated. The evolution processes of the internal molecular structures, i.e. changes in molecular orientation and crystallinity, were examined by X-ray diffraction, differential scanning calorimetry, and density method. The results suggested that the molecular orientation improved; however, the crystallinity decreased when the rolling ratio increased. The analysis of the mechanical properties revealed that the rolled composites displayed anisotropy during the rolling process. In the rolling direction, after adding 1 wt.% MWCNTs, the tensile strength increased from 58.6 to 94.3 MPa with the rolling ratio, whereas the fracture strain sharply increased to 131.5% at the rolling ratio of 60%. In addition to the mechanical properties, electrical resistivity was also investigated; notably, this property was not significantly affected by the rolling process. Furthermore, the MWCNT dispersion and morphology were investigated by scanning electron microscopy. These findings offer a simple and effective method to fabricate conductive composites with excellent mechanical properties.


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