Thermal strain of high strength polyethylene fiber in low temperature

Journal of Composite Materials

Kashima

Tsutsumi

et al. 2007

Self Cite

High-strength polyethylene fiber (Dyneema Õ , DF) has a negative linear thermal expansion coefficient in the direction of the fiber. Thermal expansion coefficients of fiber-reinforced plastics are of important applications in cryogenic use. The purpose of this study is to construct the engineering technology for the thermal strain of DF reinforced plastics (DFRP) for cryogenic engineering. In this study, we investigate the thermal expansion coefficient of unidirectional high-strength DF reinforced plastics (UD-DFRP) in which DFs with different tensile moduli (15-134 GPa) and thermal expansion coefficients are used. Furthermore, using the thermal expansion coefficient and tensile modulus of each DF fiber and the matrix resin, the thermal expansion coefficients of the DFRPs are estimated by the rule of mixtures and are compared with the measured values. The results indicate that the thermal expansion coefficient of UD-DFRP behaves in a similar way to that expected from calculations based on the rule of mixtures. In addition, relationships concerning the difference between the calculated and measured values, the difference in the thermal expansion coefficient of the fiber and the resin, and the surface treatment of the fiber (adhesivity), as well as the diameter of the fiber (the area of the interfacial bonding) are studied. The results show that all of these influence the thermal expansion coefficient of UD-DFRP. The design of negative thermal expansion coefficient of UD-DFRP is established.

Section: Thermal Expansion Coefficient and Law Of Mixturementioning

confidence: 86%

“…The properties of DFs are shown in Table 1 [1,2]. The DFs with or without surface treatment were used as reinforcement.…”

Section: Reinforcementmentioning

confidence: 99%

Thermal Expansion Coefficient of Unidirectional High-Strength Polyethylene Fiber Reinforced Plastics at Low Temperature

Journal of Composite Materials

Kashima

Tsutsumi

et al. 2007

Self Cite

“…Four kinds of DFs (Toyobo, Dyneema 1 , DF (A-D) with different draw ratio 16 were used. 17 They have different modulus 17…”

Section: Experimental Samplementioning

confidence: 99%

“…[36][37][38][39][40] In this way, the crystallinities of DFs were estimated by the measurements of solid state 13 C NMR spectra in a previous work. 17 The details of estimation of crystallinities were discussed in a previous article. 17 The crystallinities of DFs are shown in Figure 2.…”

Section: Crystallinity Of Dfsmentioning

confidence: 99%

“…11 Furthermore, a previous report elucidated that DF with higher tensile modulus showed higher negative thermal expansivity, and this relationship was explained by the fiber structure illustrated in the mechanical serialparallel model (Takayanagi-model), which consists of a crystalline/amorphous structure. 17 In this article, we apply this mechanical model introduced in our previous report 17 to the DFs for thermal conductivity. This mechanical model is composed of the following two parts by parallel combination.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermal conductivity of high strength polyethylene fiber in low temperature

J Polym Sci B Polym Phys

Fujishiro

Kashima

et al. 2005

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High strength polyethylene fiber (Toyobo, Dyneema 1 fiber, hereinafter abbreviated to DF) used as reinforcement of fiber-reinforced plastics for cryogenic use has a high thermal conductivity. To understand the thermal conductivity of DF, the relation between fiber structure and thermal conductivity of several kinds of polyethylene fibers having different modulus from 15 to 134 GPa (hereinafter abbreviated to DFs) was investigated. The mechanical series-parallel model composed of crystal and amorphous was applied to DFs for thermal conductivity. This mechanical model was obtained by crystallinity and crystal orientation angle measured by solid state NMR and X-ray. Thermal conductivity of DF in fiber direction was dominated by that of the continuous crystal region. The thermal conductivity of the continuous crystal part estimated by the mechanical model increases from 16 to 900 mw/cmK by the increasing temperature from 10 to 150K, and thermal diffusivity of the continuous crystal part was estimated to about 100 mm 2 /s, which is almost temperature independent. The phonon mean free path of the continuous crystal region of DF obtained by thermal diffusivity is almost temperature independent and its value about 200 Å . With the aforementioned, the mechanical series-parallel model composed of crystal and amorphous regions could be applied to DFs for thermal conductivity. V V C 2005 Wiley Periodicals, Inc.

The effect of γ‐irradiation on thermal strain of high strength polyethylene fiber at low temperature

J of Applied Polymer Sci

Izumi

Kitagawa

et al. 2006

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ABSTRACT:To understand the contribution to negative thermal expansion by the length of the molecular chains in high-strength ultra-high-molecular-weight polyethylene (UHMW-PE) fiber, the thermal expansion coefficient in the range of low temperature was investigated for high-strength UHMW-PE fiber (Toyobo, Dyneema®; hereinafter abbreviated to DF), irradiated by ␥-rays (␥-rays treatment) that induce the molecular scission. The molecular weight of DF decreased by ␥-ray treatment. X-ray diffraction behavior did not change by ␥-ray treatment. The melting behavior observed by DSC showed the main chain scission of DF by ␥-ray treatment. The DFs, with and without ␥-ray treatment, expand by cooling down (negative thermal expansion). The change of negative thermal expansion of DF by ␥-ray treatment was small. It is suggested that negative thermal expansion does not change by only the molecular chain scission. These results suggested that the effect of negative thermal expansion of DF in the temperature range from 213 to 303 K by the molecular chain scissions is small and that the length of extended molecular chains contributes to a negative thermal expansion a little.