Körük, Hasan (MEF Author)Considering the adverse effects of petroleum-based materials on nature, finding and developing new materials as alternatives to these chemical materials become a necessity in practice. On the other hand, these new materials need characterization to be considered and effectively used in practical applications. The acoustic properties of luffa bio fiber and composite materials are investigated in this study. First, the preparation of various luffa test samples and the method for acoustic characterization of the luffa samples is presented. Then, the acoustic absorption properties of both luffa fiber and composite materials are identified using the impedance tube method. After that, the transmission loss levels of the same luffa samples are determined. All the results are evaluated and the acoustic performances of luffa materials are highlighted

Traditional printed circuit board (PCB) laminates such as FR4 types are formed using epoxy resin and glass fiber. The most important problem with waste PCB laminates is that their recycling cycle is too long. Herein, we aimed to show whether it is possible to use plant-based fibers instead of petroleum-based fibers. In this study, we have fabricated alternative eco-friendly Luffa fiber-reinforced/epoxy PCB (Luffa-PCB) laminates using Luffa fiber instead of glass fiber. We examined the properties of Luffa-PCB laminates for potential applications as PCBs in terms of frequency dependence of dielectric permittivity, capacitance, ac conductivity, impedance, and electric modulus by using impedance spectroscopy method in a frequency ranging from 10 Hz to 10 MHz. Furthermore, we investigated the electrical resistivity properties of Luffa-PCB laminates using electrometer/high resistance meter and resistivity test fixture. All the results were compared with commonly used FR2- and FR4-type PCB laminates. According to the results obtained, it has been found that the produced Luffa-PCB laminates have adequate properties as an alternative to traditional laminates. Thus, a very important step is taken to solve the recycling problem by using plant-based fibers instead of glass fibers.

The acoustic properties of natural fiber-reinforced composites should be identified before using these materials in various engineering applications including sound and vibration isolation. This study investigates the effects of sample thickness and fiber/resin ratio on the acoustic performance of jute and luffa fiber-reinforced biocomposites. For this purpose, jute and luffa composite samples with different thicknesses and fiber/epoxy ratios are manufactured and their sound absorption coefficients (SACs) and transmission losses (TLs) are determined using impedance tube method. Thickness-dependent tendencies of the SACs and TLs of jute and luffa composites for low-, medium-, and high-frequency ranges are identified. The effect of fiber/epoxy ratio on the acoustic properties of jute and luffa composites as a function of frequency are determined. Furthermore, the SACs and TLs of some natural fiber-based samples with different thicknesses are predicted using mathematical models and the theoretical and experimental results are compared and evaluated.

Identification of the Dynamic Characteristics of Luffa Fiber Reinforced Bio-Composite Plates