scholarly journals The Effect of Dialkyl Peroxide Crosslinking on the Properties of LLDPE and UHMWPE

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3062
Author(s):  
Pollyana S. M. Cardoso ◽  
Marcelo M. Ueki ◽  
Josiane D. V. Barbosa ◽  
Fabio C. Garcia Filho ◽  
Benjamin S. Lazarus ◽  
...  
Keyword(s):  
Crystallization Process ◽  
Polymeric Materials ◽  
Morphological Properties ◽  
Ductile Material ◽  
Chemical Agent ◽  
Neat Polymer ◽  
Melting Temperatures ◽  
Dialkyl Peroxides ◽  
Dialkyl Peroxide ◽  
Ultra High Molecular Weight

Peroxide has been considered a chemical agent that can be used to tune the properties of polymeric materials. This research evaluated the influence of different concentrations of dialkyl peroxides on the mechanical, thermal, and morphological properties of linear low-density polyethylene (LLDPE) and ultra-high molecular weight polyethylene (UHMWPE). The neat polymer, as well as those with the addition of 1% and 2% by mass of dialkyl peroxides, were subjected to compression molding and immersion in water for 1 h, under controlled temperatures of 90 °C. The values of the gel content found in the samples indicated that the addition of peroxide to the LLDPE and to the UHMWPE promoted the formation of a reticulated network. The structure obtained by the crosslinking led to less reorganization of the chains during the crystallization process, resulting in the formation of imperfect crystals and, consequently, in the reduction in melting temperatures, crystallization and enthalpy. The mechanical properties were altered with the presence of the crosslinker. The polymers presented had predominant characteristics of a ductile material, with the occurrence of crazing with an increased peroxide content.

scholarly journals Mechanical and Morphological Properties of Bio-Phenolic/Epoxy Polymer Blends

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 773
Author(s):  
Ahmad Safwan Ismail ◽  
Mohammad Jawaid ◽  
Norul Hisham Hamid ◽  
Ridwan Yahaya ◽  
Azman Hassan
Keyword(s):  
Mechanical Properties ◽  
Phase Separation ◽  
Polymer Blends ◽  
Epoxy Polymer ◽  
Flexural Modulus ◽  
Polymeric Materials ◽  
Morphological Properties ◽  
Comparison Results ◽  
Unique Material ◽  
Different Types

Polymer blends is a well-established and suitable method to produced new polymeric materials as compared to synthesis of a new polymer. The combination of two different types of polymers will produce a new and unique material, which has the attribute of both polymers. The aim of this work is to analyze mechanical and morphological properties of bio-phenolic/epoxy polymer blends to find the best formulation for future study. Bio-phenolic/epoxy polymer blends were fabricated using the hand lay-up method at different loading of bio-phenolic (5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt%) in the epoxy matrix whereas neat bio-phenolic and epoxy samples were also fabricated for comparison. Results indicated that mechanical properties were improved for bio-phenolic/epoxy polymer blends compared to neat epoxy and phenolic. In addition, there is no sign of phase separation in polymer blends. The highest tensile, flexural, and impact strength was shown by P-20(biophenolic-20 wt% and Epoxy-80 wt%) whereas P-25 (biophenolic-25 wt% and Epoxy-75 wt%) has the highest tensile and flexural modulus. Based on the finding, it is concluded that P-20 shows better overall mechanical properties among the polymer blends. Based on this finding, the bio-phenolic/epoxy blend with 20 wt% will be used for further study on flax-reinforced bio-phenolic/epoxy polymer blends.

Tribological behavior of UHMWPE in water lubrication: the effect of molding temperature

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xincong Zhou ◽  
Chaozhen Yang ◽  
Jian Huang ◽  
Xueshen Liu ◽  
Da Zhong ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Friction Coefficient ◽  
Friction And Wear ◽  
Wear Loss ◽  
Content Type ◽  
Molding Temperature ◽  
Melting Temperatures ◽  
Ultra High Molecular Weight ◽  
Wear Tests ◽  
Friction And Wear Tests

Purpose Ultra-high molecular weight polyethylene (UHMWPE) is adopted in water-lubricated bearings for its excellent performance. This paper aims to investigate the tribological properties of UHMWPE with a molecular weight of 10.2 million (g mol‐1) under different molding temperatures. Design/methodology/approach The UHMWPE samples were prepared by mold pressing under constant pressure and different molding temperatures (140°C, 160°C, 180°C, 200°C, 220°C). The friction and wear tests in water were conducted at the RTEC tribo-tester. Findings The friction coefficient and wear loss decreased first and rose later with the increasing molding temperature. The minimums of the friction coefficient and wear loss were found at the molding temperatures of 200°C. At low melting temperatures, the UHMWPE molecular chains could not unwrap thoroughly, leading to greater abrasive wear. On the other hand, high melting temperatures will cause the UHMWPE molecular chains to break up and decompose. The optimal molding temperatures for UHMWPE were found to be 200°C. Originality/value Findings are of great significance for the design of water-lubricated UHMWPE bearings.

Influence of Machining Parameters of the Drilling Polymers UHMW-PE and PTFE

2015 ◽  
Vol 1120-1121 ◽  
pp. 1297-1301 ◽  
Author(s):  
Breno Ferreira Lizardo ◽  
Luciano Machado Gomes Vieira ◽  
Juan Carlos Campos Rubio ◽  
Marcelo Araújo Câmara
Keyword(s):  
Thrust Force ◽  
Polymeric Materials ◽  
Machining Parameters ◽  
New Materials ◽  
Hole Quality ◽  
Tool Geometries ◽  
Dimensional Deviation ◽  
Fiber Metal ◽  
Ultra High Molecular Weight ◽  
Quality Surface

Over the years, with the increasing development of engineering materials, the emergence of new composites, fiber metal laminated, biomaterials, metal alloys etc., and with demand for products less expensive, less polluting and more efficient, the manufacturing engineering also needs to develop to be able to process these new materials. Materials and tool geometries, intelligent mechanisms, modular machines, also follow this setting. To that end, this work comes to raise the main parameters that influence in the hole quality surface of finished product. Were used two polymeric materials, ultra high molecular weight polyethylene (UHMW-PE) and polytetrafluoroethylene (PTFE), two feed rates, three rotations and three tool geometries, allowing to identify which of these parameters have greater influence on the thrust force and the characteristics of the finished product and dimensional deviation.

Wear Evaluation of Different Polymeric Materials for Total Disc Replacement (TDR)

2011 ◽  
Author(s):  
Vaneet Singh ◽  
Cindy Ogden ◽  
Kenny Sitton
Keyword(s):  
Total Disc Replacement ◽  
Compressive Load ◽  
Polymeric Materials ◽  
Axial Rotation ◽  
Polyphenylene Sulfide ◽  
Volumetric Wear ◽  
Industrial Grade ◽  
Pin On Disc ◽  
Wear Evaluation ◽  
Ultra High Molecular Weight

In this study, we evaluated the wear of different polymeric materials. The temperatures were also monitored near the articulating surfaces. Six pin-on-disc specimens made out from industrial grade Polyetheretherketone (PEEK), medical grade PEEK, Polyacetal, Ultra High Molecular Weight Polyethylene, Polyetherimide, and Polyphenylene Sulfide. The specimens were tested under ± 8° axial rotation and constant compressive load ranging from 50N–444N. The results of study show an increase in the wear and temperature with increased load. The PEEK-on-UHMWPE material combination outperformed all other tested material combinations in terms of volumetric wear.

scholarly journals Recycled Polymer Materials as Aggregates for Concrete and Blocks

2013 ◽  
Vol 27 ◽  
pp. 53-57 ◽  
Author(s):  
Md Mostafizur Rahman ◽  
Md Akhtarul Islam ◽  
Mainuddin Ahmed ◽  
Md Abdus Salam
Keyword(s):  
Chemical Engineering ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Morphological Properties ◽  
Light Weight ◽  
Floating Structures ◽  
Different Types ◽  
Waste Polymer ◽  
Recycled Waste ◽  
Recycled Polymer

The potential of recycled waste polymeric materials as a substitute for aggregates in concrete has been investigated in the study. Two different types of waste polymer, namely polyurethane formaldehyde (PUF) based packaging waste and high density polyethylene (HDPE) were recycled and used in the experiment. Concrete and masonry poly block specimens were prepared using recycled polymer materials, and test specimens were characterized. The effects of waste polymer materials on the mechanical, physical and morphological properties of concrete and poly blocks have been investigated. The result shows that the inclusion of waste polymer materials decreases density, porosity and water absorption of concrete and poly blocks significantly. Polyurethane formaldehyde (PUF) based block exhibited lower density than that of HDPE-based concrete. Due to exceptionally low density, recycled polymer modified blocks and concrete can be used in non-load bearing structures, floating structures and where light weight materials recommended. DOI: http://dx.doi.org/10.3329/jce.v27i1.15859 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 1, June 2012: 53-57

Rotomolding and polyethylene composites with rotomolded lignocellulosic materials: A review

2020 ◽  
Vol 39 (11-12) ◽  
pp. 459-472
Author(s):  
Lumirca Del Valle Espinoza León ◽  
Viviane Alves Escocio ◽  
Leila Lea Yuan Visconte ◽  
Julio Cesar Jandorno Junior ◽  
Elen Beatriz Acordi Vasques Pacheco
Keyword(s):  
Maleic Anhydride ◽  
Polymer Matrix ◽  
Polymer Melt ◽  
Polymeric Materials ◽  
Melt Flow Index ◽  
Polymer Particle ◽  
Morphological Properties ◽  
Flow Index ◽  
Main Process ◽  
Wood Fibers

Rotomolding is a versatile process used in the manufacture of thermoplastic polymeric materials to produce large hollow plastic parts. The aim of this review article was to discuss the rotomolding process and show the properties of the polyethylene composite and rotomolded lignocellulosic fibers, which are processed for prolonged periods under temperature. The main process parameters studied are the shaft speed of the equipment, molding temperature, polymer particle size, polymer melt flow index, and amount of material, which must be well controlled to achieve a non-degraded product with homogeneous thickness and no porosity. Rotomolded composites containing sisal, pine, coir, banana, flax, and maple wood fibers, among others, have been evaluated primarily for their mechanical (impact, flexural, and tensile strength) and morphological properties. The type, content, and treatment of lignocellulosic fillers are the most widely studied variables in polyethylene-based rotomolded composites. Fiber content was the variable that most influenced mechanical properties, particularly impact strength and hardness due to the voids formed by the hydrodynamic volume between the polymer matrix and lignocellulosic filler. Chemical treatment of the fiber by mercerization with NaOH made it more hydrophobic and the addition of maleic anhydride-grafted polyethylene as a coupling agent improved the interfacial adhesion between the non-polar polymer matrix and polar filler. However, the best mechanical property results were obtained with the use of maleic anhydride-grafted polyethylene.

scholarly journals Photodegradation of UHMWPE Compounded with Annatto and Beetroot Extracts

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Alexandre Rangel de Sousa ◽  
Géssica Patrícia Dornas ◽  
Isadora Cota Carvalho ◽  
Renata Francisca da Silva Santos
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Polymer Matrix ◽  
Spectroscopic Characterization ◽  
Tensile Tests ◽  
Neat Polymer ◽  
Before And After ◽  
The Stability ◽  
The One ◽  
Ultra High Molecular Weight

We observed the anti-UV action of beetroot extract in an ultra-high molecular weight (UHMWPE) matrix. The beetroot extract and the one prepared from annatto seed also acted efficiently as pigment to the same polymeric matrix. Neat UHMWPE and UHMWPE compounded with annatto and beet extract were compression molded and tensile specimens were obtained from the molded plates and submitted to UV radiation for up to 42 days. Tensile tests were performed and it was observed that the beet extract had a stabilizing action in the polymer compared to neat polymer and the one with annatto extract. Complementary analyses showed good homogenization of the extracts through the polymer matrix indicating the possibility of use as pigment, although the annatto extract appeared to be very unstable under irradiation. Spectroscopic characterization helped to explain the stability of the extracts before and after molding.

Sign in / Sign up

Export Citation Format

Share Document