Ultrahigh Molecular Weight Polyethylene Fiber Surface Research Articles

High‐performance fiber‐reinforced composites with a polydopamine/epoxy silane hydrolysis‐condensate bilayer on surface of ultra‐high molecular weight polyethylene fiber

AbstractA bilayer structure with polydopamine (PDA) transition layer and 3‐glycidyl ether oxy‐propyl trimethoxy silane (GOPTS) hydrolysis‐condensate strengthened layer on the surface of ultra‐high molecular weight polyethylene (UHMWPE) fiber is prepared to improve the damage resistance of composites and more efficient stress transmission in composites. PDA is covered on the surface of UHMWPE fiber and then GOPTS is hydrolyzed and condensed to form inorganic ‐O‐Si‐O‐ with epoxy groups on the PDA layer. In addition, the surface activated nano‐SiO2 is dispersed in the epoxy resin to increase the strength of the matrix resin. The results show that the interfacial shear strength (IFSS), the impact strength, the flexural strength and flexural modulus of UHMWPE‐PDA‐GOPTS/EP‐SiO2 increase by 99.1%, 54.1%, 76.8%, and 36.6% respectively compared with unmodified UHMWPE/EP. The chemical compositions of the treated fiber surface are characterized by X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy (ATR‐FTIR). With the help of the scanning electron microscopy, the interface failure and reinforcement mechanism of the composites are further explored due to UHMWPE fiber shear yield deformation, UHMWPE fiber fracture, matrix resin cracking and the relative sliding friction between the fiber and matrix.

Enhanced interfacial shear strength in ultra-high molecular weight polyethylene epoxy composites through a zinc oxide nanowire interphase

The mechanical properties of fiber-reinforced composites are largely dictated by fiber-matrix interactions, where a well-adhered interface is desired. Ultra-high molecular weight polyethylene (UHMWPE) fibers suffer from poor interfacial properties due to their smooth and inert surface. Therefore, enhancing the interfacial properties of such composites will lead to an increased use in structural applications where high modulus, tenacity, low density, high impact and abrasion resistance properties are needed. In this work, an interfacial modification process consisting of an oxygen plasma surface functionalization followed by the grafting of zinc oxide nanowires (ZnO NWs) onto the UHMWPE fiber surface is investigated to improve the fiber-matrix interaction in UHMWPE composites. The UHMWPE fiber surface is subjected to varying oxygen plasma treatment durations such that the surface oxygen content can be increased to improve ZnO NW adhesion. Through single fiber pullout testing, the interfacial shear strength (IFSS) of oxygen plasma functionalized and ZnO NW coated UHMWPE fibers was shown a maximum increase of 135% with a 30 s plasma treatment prior to ZnO NWs. This increase in IFSS is attributed to an increased surface area interaction and mechanical interlocking between the fiber and matrix. The results detailed in this work demonstrate a benign, simple, and effective way to significantly improve the interfacial properties of UHMWPE fiber reinforced composites.

Copper-polydopamine composite coating decorating UHMWPE fibers for enhancing the strength and toughness of rigid polyurethane composites

In this study, ultra-high molecular weight polyethylene (UHMWPE) fibers reinforced rigid polyurethane (RPU) composites were prepared with the goal of improving strength and toughness. The satisfactory mechanical properties of the composites were mainly contributed to the copper-polydopamine composite coating. Polydopamine on the surface of UHMWPE fibers could react with polyurethane to form chemical bonds, leading to the improvement of material strength. Moreover, the deposited metal layer provided more paths for crack propagation in the composites, thus improved the toughness of the material. Compared with pure RPU, the tensile, interlaminar shear, and impact strength of polydopamine (PDA)-cooper (Cu) UHMWPE fibers/RPU composites were increased by 97.8%, 35.85%, and 2456.9%, respectively.

RETRACTED: Interfacial microstructure and properties between epoxy resin and novel organic hybrid graphene oxide modification ultra high molecular weight polyethylene fiber

Abstract An efficient chemical grafting method was developed to enhance interfacial properties of ultra high molecular weight polyethylene (UHMWPE) fiber reinforced composites. Novel organic hybrid graphene oxide (NOHGO) was successfully prepared via grafting polyetheramine (PEA) on graphene oxide (GO) surface with (3-glycidyloxypropyl) trimethoxysilan (GLYMO) as coupling agent. Even if in the extremely dilute suspension, ideal interfacial modification effect was still easily achieved via efficiently grafting NOHGOs on the surface of UHMWPE fiber. The results revealed NOHGOs were of amino groups and almost unfolding structure. NOHGOs were adhered closely on the surface of UHMWPE fiber, which seems to form a uniform tree-rings-like interfacial structure. This type of interfacial structure benefits to reduce defects of the modified fiber surface, to enhance chemical bonding at weak region (between NOHGO and fiber) in interface, and to make the propagation paths of cracks complication, as to the extremely improvement of interfacial properties. Compared with conventional organic hybrid graphene oxide (OHGO), as many as 14.9% enhancement of the interfacial shear strength (IFSS) and higher energy absorption at the interface region were found via microbond test.

Surface amine‐functionalization of UHMWPE fiber by bio‐inspired polydopamine and grafted hexamethylene diamine

Ultrahigh molecular weight polyethylene (UHMWPE) fibers exhibit excellent mechanical property, but their low surface activity limits the application in many fields. In this work, an efficient method was used to improve the surface activity and adhesion property of UHMWPE fibers. The amine functionalized UHMWPE fibers were prepared by the combination of bio‐inspired polydopamine (PDA) and grafted hexamethylene diamine (HMDA). The chemical structure of UHMWPE fibers was characterized by X‐ray photoelectron spectroscopy and attenuated total reflectance Fourier transform infrared spectroscopy. The surface morphologies and mechanical property of the fibers were investigated by scanning electron microscopy and tensile testing respectively. In addition, a single‐fiber pull‐out test was carried out to investigate the adhesion property of the fibers with epoxy resin matrix. The results showed that PDA was coated on the surface of UHMWPE fibers and then HMDA was successfully grafted on the PDA layers. The excellent mechanical property of UHMWPE fibers had no obvious change. Compared with the pristine UHMWPE fibers, the interfacial shear strength of the PDA coated UHMWPE fibers with the epoxy resin matrix improved by 28.3%, while the IFSS of the HMDA grafted UHMWPE fibers had an increase of 82.7%. Copyright © 2017 John Wiley & Sons, Ltd.

Radiation-induced graft polymerization for the preparation of a highly efficient UHMWPE fibrous adsorbent for Cr(VI) removal

A novel fibrous adsorbent containing amine and quaternary ammonium groups was prepared by radiation-induced graft of glycidyl methacrylate (GMA) onto ultra-high molecular weight polyethylene (UHMWPE) fiber and further modifying with triethylenetetramine (TETA) and glycidyl trimethylammonium chloride (GTA). The ATR-IR spectra and SEM observation demonstrated that amine and quaternary ammonium groups were immobilized onto the surface of UHMWPE fiber. The principal factors affecting the adsorption of Cr(VI) ions have been investigated including pH of the aqueous solution, contact time, temperature and coexisting anions. This novel fibrous adsorbent could effectively adsorb Cr(VI) in the range of pH 1–9, and the maximum adsorption capacity reached 295mg/g at pH 3 and 25°C based on the Langmuir isotherm. It was found that adsorption equilibrium could be achieved within 2h for initial Cr(VI) of 100mg/L, following the pseudo-second order model. The effect of coexisting anions (including SO42−, H2PO4−, NO3−and Cl−) on the uptake of Cr(VI) was investigated in detail. Additionally, the adsorption saturated fiber could be regenerated by soaking in 0.5mol/L NaOH solution, and the adsorption performance of this adsorbent could be maintained at 90% after eight cycles of adsorption-desorption. ATR-IR and XPS analysis revealed that Cr(VI) ions were adsorbed on the fiber adsorbent through ion exchange mechanism.

Catechol and epoxy functionalized ultrahigh molecular weight polyethylene (UHMWPE) fibers with improved surface activity and interfacial adhesion

Abstract In this work, a combination of bio-inspired poly(dopamine) deposition and epoxy grafting was proposed, aiming at improving the surface activity and adhesion property of ultrahigh molecular weight polyethylene (UHMWPE) fibers. Inspired by adhesive proteins in mussels, dopamine self-polymerization was used to deposit a thin adherent poly(dopamine) (PDA) film onto the surface of UHMWPE fibers. Ethylene glycol diglycidyl ether (EGDE) was then grafted through the reactions with amide and imino groups of poly(dopamine) surface via a “two-step” or “one-step” method. The chemical structure and composition of fiber surface were characterized by XPS and ATR-IR. The surface hydrophilicity and wettability was determined by water contact angle (CA) measurement. SEM images revealed the morphology changes of the fibers. TGA and gravimetric method were applied for quantitative analysis of the surface treatment of each step. Epoxy value of modified fibers was evaluated by the titration method. The results confirmed that PDA was deposited and EGDE was successfully grafted onto the surface of fibers. The interfacial adhesion properties of UHMWPE fibers/rubber composites were investigated by single-fiber pull-out test, and 67.5% improvement was achieved. Resorcinol–formaldehyde–latex (RFL) dipping further enhanced the improvement to 365.4%. Catechol and epoxy grafted UHMWPE fabrics after dipping with RFL exhibited excellent adhesion properties with satisfying aging and fatigue resistance.

Mechanical enhancement of UHMWPE fibers by coating with carbon nanoparticles

Fiber-reinforced plastic (FRP) is composed of reinforced fibers and matrix resin, and has high specific strength and low-density materials. Because of the orientation of the fibers within them, FRPs are prone to buckling damage when under compression along the axial direction of the fiber, especially flexible organic ones. The compressive performance of FRP is largely dependent on fiber properties. the buckling load of FRP will increase with the increasing of fiber’s. In this study, we developed a way to improve the compressive and bending strength of ultra-high molecular weight polyethylene (UHMWPE) fibers. Carbon nanotubes (CNTs) and vapor-grown carbon fibers (VGCFs) were coated on the surface of UHMWPE fibers by pyrrole vapor deposition. The transverse compressive strength and bending strength of single UHMWPE fibers were determined by microcompression and single fiber bending measurements, respectively. The experiment result showed that coating UHMWPE fibers with CNTs and VGCFs increased both their transverse compressive strength and bending strength. It is excepted that the improved fiber would applied in FRP for better compressive performance.

An improvement on the adhesion‐strength of laminated ultra‐high‐molecular‐weight polyethylene fabrics: surface‐etching/modification using highly effective helium/oxygen/nitrogen plasma treatment

AbstractIn this study, helium/oxygen/nitrogen (He/O2/N2)‐plasma was used to etch/modify the surface of ultra‐high‐molecular‐weight polyethylene (UHMWPE) fiber. After coated with polyurethane (PU), the plasma treated UHMWPE fabrics were laminated. It was found that the values of peeling strength between the laminated UHMWPE fabrics treated with He/O2/N2‐plasma were significantly higher (3–4 times) than that between pristine fabrics. The hydrophilic property and the value of the surface roughness of the UHMWPE fibers increased significantly after treated with He/O2/N2‐plasma. The mechanism of the oxidation/degradation of the polymers on the surface of the UHMWPE fiber during He/O2/N2‐plasma treatment was suggested. In addition, it was found that the higher content of functional groups (carbonyl, aldehyde, and carboxylic acid) on fiber surface and the higher value of surface roughness of the UHMWPE fiber treated with He/O2/N2‐plasma could significantly improve the adhesion‐strength of the laminated UHMWPE fabric. Especially, the micro‐aperture on the surface of UHMWPE fiber caused by the strenuous etching of He/O2/N2‐plasma treatment was also an important factor on improving the adhesion‐strength between the laminated UHMWPE fabrics. Copyright © 2010 John Wiley & Sons, Ltd.

Surface modification of ultra high molecular weight polyethylene fibers via the sequential photoinduced graft polymerization

In this study, a sequential photoinduced graft polymerization process was proposed to improve the poor interfacial bonding property of ultra high molecular weight polyethylene (UHMWPE) fibers. The polymerization was initiated by dormant semipinacol (SP) groups and carried out in a thin liquid layer. Methacrylic acid (MAA) and acryl amide (AM) were grafted stepwise onto the surface of UHMWPE fibers. Attenuated total reflectance infrared spectroscopy (ATR-IR) and thermo gravimetric analysis (TGA) confirmed the grafting. The analysis result of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) indicated the structure of grafted chains. Scanning electron microscopy (SEM) images and atomic force microscopy (AFM) images revealed the apparent morphology changing, and the grafted layers were observed. Interfacial shear stress (IFSS) test of the modified fibers showed an extensively improved interfacial bonding property. The active groups grafted onto the fibers would supply enough anchor points for the chemical bonding with various resins or further reactions.

Interfacial bond property of UHMWPE composite

The ultrahigh molecular weight polyethylene (UHMWPE)/hydrocarbon (PCH) composite was prepared by selecting a PCH resin as the matrix, which has the similar structure to UHMWPE fiber. The interfacial bond property between the PCH resin and UHMWPE fiber was investigated by macromechanics, micromechanics, and contact angle. The results show that the PCH resin has good wettability with the UHMWPE fiber surface. The UHMWPE/PCH composite has excellent transverse tensile strength, interlaminar shear strength, and the pull-out strength together with the outstanding interfacial bond property.

Study on The Modification of Ultrahigh Molecular Weight Polyethylene Fiber with Polar Polymers

Due to the non-polar nature of ultrahigh molecular weight polyethylene (UHMWPE), surface modification was needed to improve the adhesion of UHMWPE fibers. In this paper, UHMWPE gel fibers were treated with a solution of polar polymer during the extracting process, then the modified UHMWPE fibers were made after multi-step hot drawing. The physical and chemical changes in the fiber structure were examined with scanning electron microscopy and Fourier transform infrared absorption spectroscopy. The mechanical properties and interfacial adhesion properties of modified UHMWPE fibers were investigated with tensile testing. The results showed that polar groups were introduced into the surface of UHMWPE fiber during the treatment process; this could improve the interfacial shear strength of UHMWPE fibers without damaging the excellent mechanical properties of fibers. The interfacial shear strength of UHMWPE fiber with epoxy resin increased with increasing draw ratio. It was shown that ethylene/vinyl acetate copolymer (EVA) is an effective modifier. After modification, the shear strength of the interface between the modified UHMWPE fiber and epoxy increased by 100%, and the integrated mechanical properties of the modified UHMWPE fibers were also optimum.

Mechanical properties of fiber reinforced styrene–butadiene rubbers using surface-modified UHMWPE fibers under EB irradiation

Aiming to develop a high performance fiber reinforced rubber of SBR, a special technique using electron beam (EB) irradiation-induced graft-polymerization was applied to ultra-high molecular-weight polyethylene (UHMWPE) fibers. Although UHMWPE is chemically inert, N-vinyl formamide (NVF) could be graft-polymerized onto the UHMWPE fiber surface with this special technique. A maximum grafting percentage of 23.6% was achieved. The composite of SBR and grafted UHMWPE fibers with maximum grafting indicated a linear increase in the initial modulus and strength with the fiber content. At the fiber content of 10%, the initial modulus was improved about five times with respect to that of the pure SBR, while the strength was done about twice. At this moment, only a small reduction could be observed in the strain compared with that of pure SBR. The fiber reinforced rubber with a good performance was obtained in the system of SBR and grafted UHMWPE fibers.

Ultrahigh‐molecular‐weight‐polyethylene‐fiber surface treatment by electron‐beam‐irradiation‐induced graft polymerization and its effect on adhesion in a styrene–butadiene rubber matrix

AbstractAiming to develop a high‐performance fiber‐reinforced rubber from styrene–butadiene rubber (SBR), we applied a special technique using electron‐beam (EB)‐irradiation‐induced graft polymerization to ultrahigh‐molecular‐weight‐polyethylene (UHMWPE) fibers. The molecular interaction between the grafted UHMWPE fibers and an SBR matrix was studied through the evaluation of the adhesive behavior of the fibers in the SBR matrix. Although UHMWPE was chemically inert, two monomers, styrene and N‐vinyl formamide (NVF), were examined for graft polymerization onto the UHMWPE fiber surface. Styrene was not effective, but NVF was graft‐polymerized onto the UHMWPE fibers with this special method. A methanol/water mixture and dioxane were used as solvents for NVF, and the effects of the solvents on the grafting percentage of NVF were also examined. The methanol/water mixture was more effective. A grafting percentage of 16.4% was the highest obtained. This improved the adhesive force threefold with respect to that of untreated UHMWPE fibers. These results demonstrated that EB irradiation enabled graft polymerization to occur even on the inert surface of UHMWPE fibers. However, the mechanical properties of the fibers could be compromised according to the dose of EB irradiation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2595–2603, 2004