Effect of synthesis time on physical properties and catalytic activities of synthesized HZSM-5 on the fast pyrolysis of Jatropha waste

The catalytic fast pyrolysis of Jatropha waste using synthesized HZSM-5 zeolites was investigated using an analytical pyrolysis-GC/MS (Py-GC/MS) technique. HZSM-5 zeolite was successfully synthesized by hydrothermal method at 160 °C with various synthesis times of 0, 24, and 72 h. From the XRD results, the as-synthesized powder before crystallization (HZSM5-0 h) showed the amorphous phase, while samples with synthesis times of 24 and 72 h (HZSM5-24 h and HZSM5-72 h) showed the high crystalline phase of HZSM-5 with the main peaks at the 2θ of 7.9°, 8.8°, 23.1°, 23.7°, and 23.9°. The particle of HZSM5-72 h appeared in cubic-shaped crystal compared to the HZSM5-24 h. HZSM5-72 h had a higher surface area of 625 m²/g with an average larger pore diameter of 27.97 Å and pore volume of 0.28 cm³/g. The effect of biomass to catalyst ratios of 1:1, 1:5, and 1:10 was investigated at 500 °C. It was found that the aromatic and aliphatic selectivity depended on the synthesis time of HZSM-5 reflected in their surface areas, pore sizes, and catalyst content. The highest aromatic and aliphatic hydrocarbon of almost 95 % was obtained when a large amount of HZSM-5 (synthesized for 72 h) was used which could lead to the high heating values of bio-oils. The HZSM5-72 h also contributed to eliminate the undesirable oxygenated compounds such as acids, aldehydes, and ketones. Nevertheless, there are still a few percentages of N-containing components that may require further denitrogenation prior to utilization of the obtained liquid fuel.     

Effects of Compositions and Processing Variables on Barrier and Mechanical Properties of Liquid Crystalline Polymer/Polyethylene Blend Films

Cast films of liquid crystalline polymer (LCP) and low density polyethylene (LDPE) blends have been produced and investigated. Effects of LCP content and processing parameters, i.e., processing temperature profile, screw speed, and post-die drawing, on morphology and O₂ barrier property are presented. Increasing processing temperature and LCP content tend to enhance aspect ratios (L/D) of the LCP dispersed phase and at the same time influencing LCP structure. These effects are clearly observed when LCP content is increased from 10 % to 30 % by wt. At high temperature profiles, LCP morphologies are presented in a more or less ‘ribbon’ or ‘tape’ like structure together with a common LCP fibrillar structure. Films of 10% and 30% LCP produced at two optimum temperature profiles show a noticeable proportion of LCP tape-like structure and interestingly high barrier properties of ∼1.6 and 5.5 times that of the neat LDPE films. High barrier characteristics of such LCP/PE blend films are indicated by low oxygen transmission rate values. Apart from processing temperature effect, increases of screw speed result in films having smaller aspect ratios for both LCP fibers and ribbons; films also exhibit poorer barrier and mechanical properties. However, post-die drawing clearly demonstrates a positive effect in improving aspect ratios of the LCP domains and the resulting films' moduli. Effects of post-die drawing on enhancing films' barrier properties become more pronounced at high LCP content. By comparing with the neat LDPE film (30 μm thick) having modulus of ∼180 MPa and OTR of ∼11000 cc/m².day, the developed LCP/PE films containing 30 wt% LCP show remarkably high modulus values of ∼1100 MPa with low OTR of ∼2000 cc/m².day.