Composites polyethylene, ultra-high-modulus

Ultra-high modulus fibers such as aramid and carbon fibers have been currently utilized for composite material fabrication. Ultra-high modulus polyethylene (UHMPE) fiber is also applicable for composite fabrication because of the light weight in addition to its high modulus, vibration damping, and resistance to chemicals. However, this fiber has drawbacks such as poor interfacial adhesion with the polymer matrix of the composite because of highly hydrophobic nature of the fiber surface. 

With proper resolution of the technical problems, molecular composites should offer significant commercial promise. This will require adapting the technology to the existing commodity or engineering polymers. Polyamides appear to be the best opportunity based on the literature references. However, even commodity polymers such as polyethylene should not be ruled out. An example of this can be found in work reported by Teishev et al. [1993] where ultra high modulus polyethylene fibers were dispersed in a HOPE matrix. 

Jang JS, Moon SI, Impact and behavior of carbon fibre/ultra-high modulus polyethylene fibre hybrid composites, Polymer Composites, 16(4), 325-329, 1995. 

Li Y, Xian XJ, Choy Cl, Guo MI, Zhang ZG, Compressive and flexural behavior of ultra-high-modulus polyethylene fibre and carbon fibre hybrid composites, Composites Sci Technol, 59(1), 13-18, 1999. 

The ability to control the interface is central to successful application of adhesion in a composite. By modifying or tailoring the interface, the improved fundamental adhesion might result in the improved practical adhesion for example, various surface treatments of ultra-high modulus polyethylene fibres used as reinforcemenf in polyester and epoxy composites that changed the values of both monofilament pull-out adhesion and interlaminar shear strength. ... 

Ladizesky, N.H. and Ward, I.M., Ultra-High-Modulus Polyethylene Fibre Composites I—The Preparation and Properties of Conventional Epoxy Resin Composites. Comp. Sci. and Techn., 1986, 26, 129-164. 

Ladizesky, N.H. and Ward, IM. (1985) Ultra high modulus polyethylene composites. 

Aerospace composite structures can also employ high-performance polymeric fibres such as the aramids Kevlar (DuPont) or Twaron (Teijin Twaron), poly(p-phenyl-ene-2,6-benzobisoxazole) (PBO) (Toyobo) and high-modulus polyethylene (PE) (Dynema, Certran and Spectra). Generally ultra-high-molecular-weight PE (UHMWPE) can be considered to be inert to most environments except that the service temperature is limited to <130 °C. 

The dependency of critical fibre volume on fibre-matrix bond and the composite crack-tip toughness is demonstrated in Figure 12.4, for ultra-high density polyethylene (Spectra) fibre, with modulus of 117 GPa and 38 fim diameter. It clearly shows that to maintain a fibre content below 2% there is a need for a bond strength of about 1 MPa. I n order to accommodate fibres with bond of about 0.5 MPA, which is typical to many polymeric fibres, a fracture toughness below... 

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