KAPASITAS LENTUR, TOUGHNESS, DAN STIFFNESS BALOK BETON BERSERAT POLYETHYLENE

Abstract The common problems of concrete are brittle failure and low of tension. Fiber reinforced plastic concrete is one of the alternatives to solve the problems. This research aim is to demonstrate a contribution of Polyethylene to revise the weakness of its properties. An experiment has been conducted to observe compressive strength, toughness, modulus of rupture and stiffness of fiber-polyethylene-reinforced concrete. The results show that by adding Polyethylene as a fiber in concrete material, compressive strength increases to 120.36%, moment capacity of beam increases to 115.79% and toughness increases to 318.6% compared with normal concrete. Hence, it can be stated that the addition of Polyethylene fiber has a significant contribution to increase the concrete performances. Keywords: concrete, fiber, polyethylene, stiffness, toughness

Superior thermal conductivity and extremely high mechanical strength in polyethylene chains from {\it ab initio} calculation

The upper limit of the thermal conductivity and the mechanical strength are predicted for the polyethylene chain, by performing the {\it ab initio} calculation and applying the quantum mechanical non-equilibrium Green's function approach. Specially, there are two main findings from our calculation: (1). the thermal conductivity can reach a high value of 310 W/K/m in a 100 nm polyethylene chain at room temperature; (2). the Young's modulus in the polyethylene chain is as high as 374.5 GPa, and the polyethylene chain can sustain $32.85$ (ultimate) strain before undergoing structural phase transition into gaseous ethylene.Comment: published in J. Appl. Phys. (2012

The Optical Behavior of Polyethylene Spherulites

Polyethylene was crytallized from the molten film under temperature gradient. As a result, the optically positive spherulites were observed, though only the negative spherulites had been observed previOusly in polyethylene. When the radial structure units twisted regulary in a spherulite are formed parallel to the surface of the film, the spberulite is usually optically negative in polyethylene. In this study, the temperature gradient normal to the surface of the film gives so significant tilt of the radial structure units formed to the surface of the film that the radial refractive index becomes larger than the tangential one under the transmitted polarized light and the spherulites have optically positive behavior. The optical behaviors of the polyethylene spherulites and the crystallizing condition were studied and discussed

Method for casting polyethylene pipe

Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene

FDM preparation of bio-compatible UHMWPE polymer for artificial implant

Due to its properties of high wear, creep resistance, high stiffness and strength, Ultra-High Molecular Weight Polyethylene (UHMWPE) was developed to eliminate most metallic wear in artificial implant, which conventionally found in stainless steel, Cobalt Chromium (Co-Cr) and Titanium (Ti) alloys. UHMWPE has an ultra-high viscosity that renders continuous melt-state processes including one of the additive manufacturing processes, Fused Deposition Modeling (FDM) ineffective for making UHMWPE implant. Attempt to overcome this problem and adapting this material to FDM is by blending UHMWPE with other polyethylene including High Density Polyethylene (HDPE) and Polyethylene-Glycol (PEG) which provide adequate mechanical properties for biomedical application along with the improvement in extrudability. It was demonstrated that the inclusion of 60% HDPE fraction has improved the flowability of UHMWPE in MFI test and showing adequate thermal stability in TGA

Hybrid materials based on polyethylene and MCM-41 microparticles functionalized with silanes: catalytic aspects of in situ polymerization, crystalline features and mechanical properties

New nanocomposites based on polyethylene have been prepared by in situ polymerization of ethylene in presence of mesoporous MCM-41. The polymerization reactions were performed using a zirconocene catalyst either under homogenous conditions or supported onto mesoporous MCM-41 particles, which are synthesized and decorated post-synthesis with two silanes before polymerization in order to promote an enhanced interfacial adhesion. The existence of polyethylene chains able to crystallize within the mesoporous channels in the resulting nanocomposites is figured out from the small endothermic process, located at around 80 C, on heating calorimetric experiments, in addition to the main melting endotherm. These results indicate that polyethylene macrochains can grow up during polymerization either outside or inside the MCM-41 channels, these keeping their regular hexagonal arrangements. Mechanical response is observed to be dependent on the content in mesoporous MCM-41 and on the crystalline features of polyethylene. Accordingly, stiffness increases and deformability decreases in the nanocomposites as much as MCM-41 content is enlarged and polyethylene amount within channels is raised. Ultimate mechanical performance improves with MCM-41 incorporation without varying the final processing temperature

Penelitian Pengaruh Penggunaan Riklim Politilen Terhadap Sifat Ketahanan Pukul Dan Kekerasan

The aim of this research is to know further about the influence ot polyethylene reclaim to the characteristic of impact resistance and high density polyethylene (HDPE) compound.The research is done by making HDPE compound with the addition of polyethylene reclaim with various procentage of quantity.In fact the addition on of HDPE reclaim into pure HDPE doesn\u27t influence the hardness of the compound produced, but it influence the impact resistance to signification phase P 0,05 by linear aquation Y = 10,26 + 0,0887.The compound hardness is approximately 63,2 – 64,0 shore D, and impact resistance is approximately 10,83 – 18,91 kgcm/cm in various variation

Growing Sweetcorn in Alaska's Cool Environments

Sweet corn can be grown in Alaska's cool environments by employing clear polyethylene mulch to raise soil temperatures. Rows should be run north and south, spaced about 5 feet apart for 4-foot wide mulch. Weeds can be controlled under clear polyethylene mulch by spraying with atrazine after seeding and before mulching

Low temperature thermal expansivities of polyethylene, polypropylene and their mixtures

Low temperature measurements of length- temperature curves of polyethylene, polypropylene, mixtures of polyethylene and polypropylene, and copolymer