Ultra-high Molecular Weight Polyethylene Fibers Research Articles

High strain rate compressive response of ultra-high molecular weight polyethylene fibre composites

The mechanisms of deformation during the dynamic in-plane compression of [0o/90o]n (cross-ply) ultra-high molecular weight polyethylene (UHMWPE) fibre composites with polymeric matrices have been investigated for strain rates in the range 0.01s−1 to 4000s−1. The measured strain rate sensitivity was mild for strain rates less than about 100s−1, but increased sharply at higher rates. X-ray computed tomography and optical microscopy revealed that over the range of strain rates investigated here, the deformation mechanism was kinking (micro-buckling) of the plies with a kink band width of about 1 mm. Ply delamination was also observed, but only during softening phase of the response after the peak strength had been attained. To gain a mechanistic understanding of the observed strain rate sensitivity, finite element (FE) simulations were used to model the compression experiments. For these calculations, each specimen ply was explicitly modelled via a pressure-dependent crystal plasticity framework that accounts for the large shear strains and fibre rotations that occur within each ply in the kink band. Calculations were conducted in the limits of perfectly-bonded and completely un-bonded plies. Good agreement between measurements and predictions was obtained when plies were assumed to be perfectly bonded, confirming the hypothesis that ply delamination plays a small role in setting the peak strength as well as the compressive response of the composite at moderate levels of applied strain. The calculations also show that misalignment of the specimen between the compression platens strongly influences the compression response and especially the initial stiffness. Importantly, the FE calculations reveal that over the range of strain rates investigated here, inertial stabilisation has a negligible contribution to the strong rate sensitivity observed for strain rates above 100s−1 and that this sensitivity is primarily associated with the strain rate sensitivity of the polymeric matrix.

Performance evaluation of fiber-based ballistic composites against laser threats

The interaction between a laser and a composite material has been an intense subject within the past decade and become an emerging field for the defense and manufacturing industry since high-power lasers were initiated to be utilized for the directed-beam applications. In this study, a specially developed composite material for the ballistic applications was shined to a continuous wave (CW) laser beam at 915 nm. The ballistic material was composed of 77 layers of the single sheet of the SR-3136 by Spectra Shield® from Honeywell consisting of ultra-high molecular weight polyethylene (UHMW-PE) fibers reinforced with low-density PE (LD-PE) fibers and a polyurethane-based thermoplastic resin. At the instant of the exposure, the region of interest was completely evaporated and punctured with a slight swelling around the hole where the temperature was over 450 °C. The composite material was drilled completely upon exceeding 20 kJ of laser energy. The chemical and physical changes on the composite material after the laser exposure were extensively studied by a combination of techniques including High-Resolution Scanning Electron Microscopy (HR-SEM), Energy Dispersive X-ray Spectroscopy (EDX) and X-ray Photoelectron Spectroscopy (XPS). The physical properties of a single layer of the SR-3136 were also studied using HR-SEM, UV-VIS-NIR Absorption Spectroscopy, Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC) and XPS. The research presented here reveals the first study on the effects of the high-power laser beam irradiance on the fiber-reinforced composite materials utilized for the ballistic protection.

Thermal and Mechanical Analysis of Polyethylene Homo-Composites Processed by Rotational Molding.

This work is aimed at studying the suitability of ultra-high molecular weight polyethylene (UHMWPE) fibers for the production of polyethylene homo-composites processed by rotational molding. Initially pre-impregnated bars were produced by co-extrusion and compression molding of UHMWPE fibers and linear low-density polyethylene (LLDPE). A preliminary screening of different processing routes for the production of homo-composite reinforcing bars was performed, highlighting the relevance of fiber impregnation and crystalline structure on the mechanical properties. A combination of co-extrusion and compression molding was found to optimize the mechanical properties of the reinforcing bars, which were incorporated in the LLDPE matrix during a standard rotational molding process. Apart from fiber placement and an increase in processing time, processing of homo-composites did not require any modification of the existing production procedures. Plate bending tests performed on rotational molded homo-composites showed a modulus increase to a value three times higher than that of neat LLDPE. This increase was obtained by the addition of 4% of UHWMPE fibers and a negligible increase of the weight of the component. Dart impact tests also showed an increased toughness compared to neat LLPDE.

Impact of twisting high-performance polyethylene fibre bundle reinforcements on the mechanical characteristics of high-strength concrete

The quasi-static and dynamic mechanical behaviours of the concrete reinforced by twisting ultra-high molecular weight polyethylene (UHMWPE) fibre bundles with different volume fractions have been investigated. It was indicated that the improved mixing methodology and fibre geometry guaranteed the uniform distribution of fibres in concrete matrix. The UHMWPE fibres significantly enhanced the splitting tensile strength and residual compressive strength of concrete. The discussions on the key property parameters showed that the UHMWPE fibre reinforced concrete behaved tougher than the plain concrete. Owing to the more uniform distribution of fibres and higher bonding strength at fibre/matrix interface, the UHMWPE fibre with improved geometry enhanced the quasi-static splitting tensile strength and compressive strength of concrete more significantly than the other fibres. The dynamic compression tests demonstrated that the UHMWPE fibre reinforced concrete had considerable strain rate dependency. The bonding between fibres and concrete matrix contributed to the strength enhancement under low strain-rate compression.

Research of the Resistance of Reinforced Polymeric Composite Materials to Hydro-Abrasive Action

The results of the research of the resistance of reinforced polymeric composite materials to hydro-abrasive action are presented. Hydro-abrasive wear research was carried out on a specially developed device that makes it possible to study the wear resistance of materials and coatings under impact conditions of loosely suspended abrasive particles simulating the flow of a hydro-abrasive medium. Composites based on polyester resin and polyurethane reinforced with ultra-high molecular weight polyethylene (UHMWPE) fibers and glass fibers were chosen as the objects for the study. An analysis of the intensity and nature of wear of these composites in compared with structural steel, UHMWPE and polyurea was carried out.The analysis of the obtained research results shows that UHMWPEis the most resistant to hydro-abrasive effects. However, the high cost and variation of the traditional technology of manufacturing composite products using UHMWPE as a lining material shows the advantage of using composite materials reinforced with oriented UHMWPE fibers.

Ultra-High Molecular Weight Polyethylene Fibers/Epoxy Composites: Effect of Fiber Treatment on Properties

The properties of ultra-high molecular weight polyethylene (UHMWPE) fibers reinforced epoxy resin composites were studied and the effects of the fiber surface treatment were investigated. The results showed that the surface treatment increased the roughness, O-containing groups (especially -OH groups), crystallinity and improved the wettability of UHMWPE fibers. The impact strength of the treated UHMWPE fibers/epoxy composites reached the maximum of 92.6 kJ/m2, which was higher than that of pure epoxy and as-received fiber composites. The tensile strength of both as-received and treated fiber composites showed lower than the pure epoxy. However, the tensile modulus was observably increased. The bending strength and modulus of the treated UHMWPE fibers/epoxy composites were 26.2 % and 26.0 %, higher than those of pure epoxy, respectively. The friction coefficients of the two types of composites were both increased. The dynamic mechanical analysis (DMA) results showed that Tg shifted toward higher temperatures and the reduction of tan δ peak of the treated UHMWPE fibers/epoxy composites indicated the adhesion of treated fiber with resin matrix was better than that of as-received fibers, which was in accord with the scanning electron microscope (SEM) analysis. The adding of the treated UHMWPE fibers to the epoxy matrix offered a stabilizing effect against the decomposition.

Rewritable Optical Patterns in Light-Responsive Ultrahigh Molecular Weight Polyethylene

Spiropyran is used as a photochromic dye to create colored patterns in highly drawn ultrahigh molecular weight polyethylene (UHMW PE) films. The dye is incorporated in highly crystalline, drawn UHMW PE tapes and fibers and isomerizes to its merocyanine state upon UV light irradiation, resulting in a color change from transparent to purple. The isomerization from merocyanine to spiropyran to erase the color can be simply induced by using heat or a green LED light. The combination of the use of a mask and the reversibility of the isomerization results in colored patterns that can be written, erased, and rewritten using UV light and heat or green LED light.

Investigation the Properties of Silicone Rubber Blend Reinforced by Natural Nanoparticles and UHMWPE fiber

Investigation the Properties of Silicone Rubber Blend Reinforced by Natural Nanoparticles and UHMWPE fiber

Natural fiber-reinforced high-density polyethylene composite hybridized with ultra-high molecular weight polyethylene

A great deal of research and development work has been recently conducted on natural fiber-reinforced polymer matrix composite for its abundancy, low density, excellent damping characteristic, and good mechanical properties. However, the low strength of natural fiber composite has limited its use to only low stress applications. The purpose of this work is to develop a natural fiber hybrid material with both enhanced strength and failure strain using a novel approach and study the effect of the processing temperature on its microstructure and performance. High-strength ultra-high molecular weight polyethylene fabrics are co-molded onto the surfaces of a kenaf fiber high-density polyethylene-based composite material by single-step compression molding. The status of the ultra-high molecular weight polyethylene fabrics at different processing temperatures is investigated using microscopic analysis. The tensile strength and impact strength of the hybrid material are evaluated. It is found that its tensile strength is increased by more than 90% with only 8% ultra-high molecular weight polyethylene fiber reinforcement added and its low density is maintained.

Investigation of tear strength of an airship envelope fabric by theoretical method and uniaxial tear test

This article proposed a new convenient method to obtain tear strength of an airship envelope fabric, which is a laminated plain weave fabric with the ultra-high molecular weight polyethylene fibers. First, a modified formula based on Maekawa’s empirical formula was derived. Uniaxial tear tests were then conducted on three series of single-edge notched specimens with varying widths and their critical tear stresses were measured. The experimental result showed that critical tear stress decreases with the reduction of specimen width when initial crack length is fixed. Afterward, the tear stresses of the fabric were simulated by Maekawa’s empirical formula, the modified formula, and Thiele formula. By comparing the theoretical results with the experimental results, the modified formula was verified to be consistent well with the test data. Finally, an equation was derived, which shows tear strength of this fabric decreases as initial crack length increases. For instance, when the initial crack length is 31.75 mm, the tear strength is only 44.52% of the tensile strength.

A novel ion-imprinted amidoxime-functionalized UHMWPE fiber based on radiation-induced crosslinking for selective adsorption of uranium.

A novel uranium-imprinted adsorbent (AO-Imp fiber) was prepared by radiation-induced crosslinking of amidoxime-functionalized ultra-high molecular weight polyethylene fiber (AO fiber). The porous structure was characterized by scanning electron microscopy (SEM) and positron annihilation lifetime (PAL) spectroscopy after ion imprinting. This ion-imprinted fiber exhibited enhanced adsorption selectivity for uranium in the form of both UO22− and [UO2(CO3)3]4− in batch experiments. Compared with AO fiber, the adsorption capacity of the AO-Imp(250) fiber for uranium increased from 0.36 mg g−1 to 1.00 mg g−1 in simulated seawater and from 5.02 mg g−1 to 12.03 mg g−1 in simulated acid effluent, while its adsorption capacities for other co-existing metal ions were particularly low. This study provides an approach to prepare ion-imprinted adsorbents without introducing crosslinking reagents, which may be a promising method for uranium extraction.

Использование констант ровингов из углеродных волокон и сверхвысокомолекулярного полиэтилена для расчёта плотности однонаправленных композитов

Использование констант ровингов из углеродных волокон и сверхвысокомолекулярного полиэтилена для расчёта плотности однонаправленных композитов

A general approach for the study of kink band broadening in fibre composites and layered materials

The progressive non-linear mode of deformation known as steady-state kink band broadening is analysed for fibre composites and layered materials. The mode of deformation is investigated using an analytical, a semi-analytical model and a finite-element model. The semi-analytical model is based on a constitutive model, where independent material behaviour can be given for two constituents. The analytical model assumes rigid fibres and results in a transcendental equation for the kink band broadening state. Both the analytical and semi-analytical model use a Maxwell construction to determine the steady-state, which is done by equating the internal and external work. The influence of size-effects are explored and two case studies are performed; in the first case study the finite element model and semi-analytical model are used upon a carbon fibre-reinforced PEEK composite. The second case study is on a layered composite made from ultra high molecular-weight polyethylene fibres with a kink band developing on ply level.

Experimental Research on Mechanical Properties of Steel-UHMWPE Hybrid Fiber Reinforced Concrete

The mechanical properties of a new type of hybrid fiber reinforced concrete (HFRC) which was reinforced by the steel fiber and the ultra-high molecular weight polyethylene (UHMWPE) fiber were researched. The effects of the fiber hybrid ratio on the strength and cracking-resistance properties of concrete were studied through the split-tensile and the cubic-compression tests on 16 types of HFRC. The result shows that the hybrid of the steel fiber and UHMWPE fiber can play a multi-layered role in crack-resistance properties of concrete. The strengths of HFRC is further increased when the UHMWPE fiber are mixed on the basis of the steel fiber. When the fiber volume content of UHMWPE is extra added by 0.3%, the tensile strength increases by 13.64%, 49.49% or 8.08%, and the compressive strength increases by 13.51%, 15.49% or 14.57% compared with the single steel fiber reinforced concrete as the fiber content is 0.5%, 1.0% or 1.5%. The UHMWPE fiber has more obvious effects on material strength compared with polypropylene fiber when it is mixed with the steel fiber reinforced concrete.

Polyethylene-based single polymer laminates: Synergistic effects of nanosilica and metal hydroxides

This work aims to investigate the fire performance of novel polyethylene-based single polymer composites. Fumed silica nanoparticles and magnesium hydroxide microfiller were added at an optimized concentration to a linear low-density polyethylene matrix, which was then reinforced with ultra-high molecular weight polyethylene fibers. Through the optimization of the production process, it was possible to limit the porosity inside the single polymer composites, thus retaining the pristine mechanical properties of the fibers. The addition of SiO2 and magnesium hydroxide determined an increase in the elastic modulus in both the longitudinal and transversal direction, but it concurrently led to a reduction in ductility, especially in the transversal direction. The fillers were proved to bring interesting improvements of the thermal degradation resistance and of the flame behaviour. Thermogravimetric analysis tests highlighted an increase in the onset degradation temperature and in the temperature associated to the maximum degradation rate. Moreover, both the oxidation onset temperature and limiting oxygen index were considerably improved. Cone calorimetry tests evidenced that filled single polymer composites were characterized by lower peak heat release rate and total heat released with respect to neat single polymer composites.

Development of Hydrogen-Rich Benzoxazine Resins with Low Polymerization Temperature for Space Radiation Shielding.

A systematic study has been carried out to develop a material with significant protection properties from galactic cosmic radiation and solar energetic particles. The research focused on the development of hydrogen-rich benzoxazines, which are particularly effective for shielding against such radiation. Newly developed benzoxazine resin can be polymerized at 120 °C, which meets the low-temperature processing requirements for use with ultrahigh molecular weight polyethylene (UHMWPE) fiber, a hydrogen-rich composite reinforcement. This highly reactive benzoxazine resin also exhibits low viscosity and good shelf-life. The structure of the benzoxazine monomer is confirmed by proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. Polymerization behavior and thermal properties are evaluated by differential scanning calorimetry and thermogravimetric analysis. Dynamic mechanical analysis is used to study chemorheological properties of the benzoxazine monomer, rheological properties of the cross-linked polybenzoxazine, and rheological properties of UHMWPE-reinforced polybenzoxazine composites. The theoretical radiation shielding capability of the composite is also evaluated using computer-based simulations.

Thermal Conductivity of poly-p-phenylene-2,6-benzobisoxazole Film along the In-Plane Axis in the 10–300 K Temperature Range

The thermal conductivities of compression molded thin films of poly-p-phenylene-2,6-benzobisoxazole (PBO) were measured in directions along an in-plane axis in the 10–300 K temperature range by a steady-state heat flow method, with interest in the use of the material for superconductivity applications. The thermal conductivities of the PBO films increased from 0.3 W/mK to 9.0 W/mK with increasing temperature from 10 K to 300 K and these were much higher than those of polyimide films, epoxy resin and glass fiber reinforced plastics at all temperatures. The 9.0 W/mK at 300 K was 60% of that of stainless steel (SUS304). It was 6 W/mK at 150 K, which was half that of SUS304 and was 3.3 W/mK at 77 K, which was 33% of that of SUS304. The thermal conductivities of the PBO films were lower than those of a cloth of high strength ultrahigh molecular weight polyethylene fiber reinforced plastics in the 30 K–180 K temperature range and were almost equivalent to its values in the 180 K–300 K temperature range. The main contribution to the thermal conduction in the PBO films was from thermal phonon conduction along the molecular chains. Although many kinds of high thermal conductivity polymeric materials have been prepared by a uni-directional drawing process or by adding high thermal conductive additives, the PBO film showed high thermal conductivity without a uni-directional drawing process or high thermal conductive additive.

A Study of the Mechanical Behavior and Crystal Structure of UHMWPE/HDPE Blend Fibers Prepared by Melt Spinning

Ultrahigh molecular weight polyethylene (UHMWPE) and high-density polyethylene (HDPE) blend fibers with the highest tensile strength of 1.13 GPa were prepared by a melt spinning process. The crystal structure and mechanical behavior of the as-spun filaments and fibers were studied by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), sound velocity orientation test and tensile strength test. The results suggested that the degree of molecular chain orientation, crystallinity and mechanical properties of the blend fibers were improved by blending with the low melt flow index (MFI) HDPE. The crystal grains of low MFI HDPE blend fibers that were formed by more highly oriented molecular chains could be stretched more effectively in the drawing direction, and the improved mechanical properties were due to the more regular and compact crystal structure.

Reattachment of an osteotomized greater trochanter in total hip arthroplasty using an ultra-high molecular weight polyethylene fiber cable

BackgroundThe optimum approach in total hip arthroplasty (THA) should reduce the risk of postoperative dislocation or limping, be applicable in every case, and be reusable in the future. The purpose of this study was to introduce our transgluteal approach for THA and to evaluate the type and frequency of complications around the greater trochanter. MethodsThis study retrospectively evaluated 892 THA cases between January 2010 and March 2015 performed using our transgluteal approach that osteotomized only the lateral anteroinferior greater trochanter. The trochanteric fragment was reattached using one of three different protocols: Group A, three non-absorbable polyester sutures; Group B, two non-absorbable polyester sutures and one ultra-high molecular weight polyethylene (UHMWPE) fiber cable; or Group C, two UHMWPE fiber cables. Postoperative complications were assessed and recorded, and univariate logistic regression analyses were performed to determine whether risk factors and radiological complications around the greater trochanter were correlated. ResultsNone of the hips required revision for infection, dislocation, or limping. The rate of radiological complications around the greater trochanter at 1 year was 19.2% in Group A, 16.3% in Group B, and 7.9% in Group C (p < 0.001). Risk factors for radiological complications included the patient's disease or the surgeon's experience in Group A and the patient's age or the surgeon's experience in Group C. In the relationship between postoperative pain around the greater trochanter and radiological complications, there were no significant differences in all groups; no group interaction was observed (p= 0.3875). ConclusionThe UHMWPE fiber cable was effective to reduce complications of the reattached osteotomized greater trochanter in THA.

Strength tests of fiber-reinforced composite with ultra-high molecular weight polyethylene

Introduction. Ultra-high molecular weight polyethylene (UHMWPE) fibers are inert, thus their adhesion to the organic polymer matrix of the composite material may not be rewarding. Therefore, these types of fibers have not yet come into widespread use in dentistry. Aim of the study. To evaluate selected strength characteristics of the UHMWPE fiber-reinforced composite whose surface was chemically activated and then impregnated with a mixture of dimethacrylate resins and coated with a microhybrid composite material. Material and method. Tests were carried out which allowed to evaluate selected mechanical properties of the material under static stretching and shearing. Results. Based on the experiments the following values were calculated: Young’s elastic modulus Et = 3583.97 ± 1325.75 MPa, tensile stress σ = 59.73 ± 7.54 MPa, maximum tensile force Fmax = 121.23 ± 17.92 N, linear extension εt = 0.03 ± 0.003 and tangential stress τt = 4.99 ± 1.19 MPa. The loss of adhesion of the material to the hard tissues of the tooth was typical of the mixed adhesive-cohesive breakthrough. Conclusions. The study revealed high and desired mechanical strength in both the tensile test and in the shear test, which may justify the effective use of this type of fibers in clinical practice. The phenomena of saturation and penetration of the resin into the space between the fiber bundles occurring in the oxidation process did not negatively affect the mechanical properties of the material tested.