NC State
  • Researchpp 7207-7222Abdullah, H. H., Zakaria, S., Anuar, N. I. S., Mohd Salleh, K., and Syed Jaafar, S. N. (2020). "Effect of harvesting time and water retting fiber processing methods on the physico-mechanical properties of kenaf fiber," BioRes. 15(3), 7207-7222.AbstractArticlePDF

    Fiber processing is an important factor that affects the physical and mechanical properties of long kenaf fiber. The physical-mechanical properties, such as color, tensile strength, and moisture regain (MR), are the main characteristics that influence the processing and performance on the final products from kenaf fiber. The objective of this research was to evaluate the physical and mechanical properties of kenaf fiber at the week of planting, with different processing methods that were planted in a selected location in Malaysia. Kenaf fiber was separated by the water retting method, where the combination of water retting and mechanical retting was based on the available facilities and proficiency at the sites. The tensile strength and chemical composition of kenaf fiber showed large variability for every location collected and for each processing technique used. Visual observations and color testing indicated that kenaf fiber with extended water immersion exhibited higher lightness and smoother fiber. A slight reduction in moisture regains was observed with increased crystallinity index. The differences among properties of the kenaf fiber that were influenced by harvesting week and processing methods could give some references and overview for the planters, suppliers, industries, and researchers to identify the suitable fiber quality for their targeted final products.

  • Researchpp 7223-7233Bian, Y., Sheng, B., and Zhou, A. (2020). "An approximate solution of compact test specimen for mode I fracture test by variational approach: Applied to fibrous composite," BioRes. 15(3), 7223-7233.AbstractArticlePDF

    The present work presented an approximate solution for a compact test (CT) specimen that was employed as a standard test provided by ASTM E399-19 (2019). The variational method was employed to obtain the solution. The method used a two-step strategy to approximate the displacement response of the CT specimen. The first step was to obtain the general form of displacement solution, and then, the Rayleigh-Ritz approach was employed to modify the solution of the first step. A compliance equation of the CT specimen was obtained, and furthermore, the formula to calculate the stress intensity factor was obtained. The solution was validated by finite element (FE) model and the formula specified in ASTM E399-19 (2019). It was concluded that the calculation results of the proposed solution agreed well with the results of the FE model prediction for the ratio of initial crack length-to-ligament length, which was in the range of 0.25 to 0.35. Furthermore, compared to the results predicted by using the formula addressed in ASTM E399-19 (2019), the method proposed in the present study can achieve closer results than that of the FE model.

  • Reviewpp 7234-7259Xu, Y., Liu, Y., Chen, S., and Ni, Y. (2020). "Current overview of carbon fiber: Toward green sustainable raw materials," BioRes. 15(3), 7234-7259.AbstractArticlePDF

    Lignin, as a potential precursor of carbon fiber, has the characteristics of abundant reserves, renewable and high carbon content, and its application in the preparation of carbon fibers has substantial cost advantages if some important processing and quality hurdles can be overcome. This paper reviews the preparation process of lignin-based carbon fibers, and moreover, describes the characteristics of carbon fiber prepared by different precursors compared with the presently used precursors. Three preparation methods for lignin-based carbon fibers are introduced: melt spinning, solution spinning, and electrospinning. The applicability, advantages, and disadvantages of the three preparation methods are analyzed from the aspects of process conditions and performance characteristics. Possible directions for future research are considered, with the goal of providing a reference for further study of lignin-based carbon fibers.

  • Reviewpp 7260-7287Triantafillopoulos, N., & Koukoulas, A. A. (2020). "The future of single-use paper coffee cups: Current progress and outlook," BioRes. 15(3), 7260-7287.AbstractArticlePDF

    The expanded use of environmentally friendly and sustainable foodservice packaging continues to be a prime focus of stakeholders across the foodservice value chain. Paper-based coffee cups is one product segment where effective recycling of waste cups remains elusive. As a result, material substitutes for polyethylene liners are emerging to solve the problem of waste cups. In this paper, current and emerging commercial material technologies used in the production of paper-based coffee cups that are readily recyclable with other paper grades are reviewed. Many of these material solutions are also compostable. Special attention is paid to the rapidly evolving, alternative large-scale production of bioplastics. Multiple efforts to effectively develop a more environmentally friendly paper cup are also examined. It is clear that broad adoption of proposed solutions will require an integrated commitment and approach to circular economics. Specifically, this includes: changes in consumer behavior; brand owner initiatives to meet sustainability goals; governmental policies that limit or forbid use of fossil-based cups; and easily accessible infrastructures at the consumer level for the collection, separation, and processing of biodegradable cups.

  • Reviewpp 7288-7308Brahmia, F. Z., Horváth, P. G., and Alpár, T. L. (2020). "Effect of pre-treatments and additives on the improvement of cement wood composite: A review," BioRes. 15(3), 7288-7308.AbstractArticlePDF

    Cement wood composites (CWC) are a popular construction material. Lightweight or panel-wise wood-based buildings have a growing market in central Europe. Requirements and regulations on both the global and national level are forcing continuous developments. This paper summarizes the research achievements in improving the hygroscopic and mechanical properties and shortening the manufacturing time of CWC via pre-treatments and additives. In addition, new perspectives on enhancing its fire resistance properties by using fire retardant pre-treatments are discussed. CWC without any pre-treatment is a material within the B-s1, d0 category of fire resistance. Using fire retardants could upgrade it to the category A1 but the fire retardants should not affect the primary properties of CWC. There are a number of potential fire retardants of wood that may be used, such as phosphorus, boron, and magnesium compounds.