Effect of mold temperature on short and long-term mechanical properties of PBT

Abstract

Abstract. In this work, the effect of mold temperature variation on the short-term mechanical properties obtained from the tensile and Charpy impact tests, and the long-term mechanical properties obtained from dynamic mechanical loading and flexural creep of injection molded polybutylene terepthalate (PBT) are reported. It has been observed that the effect of changing the processing condition viz. mold temperature on the viscoelastic properties are more pronounced when their long-term behavior is tested. The tensile and impact properties showed only a negligible effect to the change in mold temperature. Further, analysis of the creep curves by applying a four-element Burger model presented a comprehensive understanding of their long-term viscoelastic behavior with respect to the change in mold temperature.

Sustainable biocarbon as an alternative of traditional fillers for poly(butylene terephthalate)‐based composites: Thermo‐oxidative aging and durability

“…The degree of crystallinity ( X c ) of the PBT composites was calculated from the ratio of area under the first melting peak of the DSC thermogram to the enthalpy of melting for 100% crystalline PBT as shown in eq. . where Δ Hm is the enthalpy of melting for the sample, Δ H 100 is the enthalpy of melting for 100% crystalline PBT, that is, 145.0 J g −1 , and w f is the weight percent of the filler loadings (0.25 in this case).…”

“…where ΔHm is the enthalpy of melting for the sample, ΔH 100 is the enthalpy of melting for 100% crystalline PBT, that is, 145.0 J g −1 , 33 and w f is the weight percent of the filler loadings (0.25 in this case).…”

Estimating the creep strain to failure of PP at different load levels based on short term tests and Weibull characterization

“…L1 (t 2B ) ( Figure 5). Figure 5 shows the LVE estimation of the creep strain to failure as a function of the uploading time determined from the measured tensile test curve and its Weibull distribution based approximation fitted by using Equation (12). The goodness of this fitting is characterized by the high determination coefficient (R 2 = 0.995) (mean squared error in strain is 0.075%) where the parameters a, k, and !…”

“…The accuracy can be improved by assessing the relationship between V !2B and t 0 which can be performed in the knowledge of Equation (12). Figures 11 and 12 show the curves calculated on the basis of those in Figure 10 and the measured creep strain increment values versus the uploading time and the strain load level.…”

“…In general the Williams-Landel-Ferry (WLF) or the Arrhenius equation or some combination of them is applied to determining the shift factor necessary for constructing the long term master curve [6][7][8][9][10]. Power law type approximations like Nutting's or Findley's ones [6,8,11] or simple rheological models such as Standard Solid or Burgers or their generalized forms [1][2][3][4][5]12] can give a simple solution to extrapolate the measured data or to describe the master curve mathematically. In some cases constitutive mechanical models are developed using measured material constants and numerical analysis [13] or finite element models are created to describe thermoelastic creep [14].…”