نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 دانشجوی کارشناسیارشد مهندسی چوب و فرآوردههای سلولزی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران.
2 استادیار، گروه مهندسی چوب و فرآوردههای سلولزی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران.
3 استاد، گروه مهندسی چوب و فرآوردههای سلولزی، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران.
4 استادیار، گروه مهندسی چوب و فرآوردههای سلولزی، دانشکده منابع طبیعی، دانشگاه علوم کشاورزی و منابع طبیعی، ساری، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Abstract
Background and Objectives: The implementation of a logging ban period restricted the exploitation of ecologically durable forest trees, and was focused toward the cultivation and utilization of fast-growing species. To enhance the application of these species—such as poplar (Populus spp.)—modifying their inherent weaknesses is critical. This study investigates the effects of soybean oil functionalization and different conditions of combined modification using functionalized vegetable oil/styrene monomer on properties of poplar wood.
Materials and Methods: Poplar wood samples were divided into 9 groups containing: control, modified with raw and epoxidized soybean oil, styrene monomer, and a combination of epoxidized soybean oil/styrene in three ratios (10/90, 20/80, and 30/70), and a two-step modification process with raw and functionalized soybean oil/styrene. All samples modified with vegetable oil were heated at 120°C, and samples containing polymer (styrene, alone or following oil modification) were heated at 90°C.
Results: Based on the results of Fourier transform infrared (FTIR) spectroscopy, modification with functionalized soybean oil increased hydroxyl, carbonyl, and ether groups in wood samples. In two-step process, modification of wood with epoxidized soybean oil decreased styrene uptake in second stage. The highest modifying agent uptake and weight gain were measured in samples which were modified with two-step raw oil/styrene. Scanning electron microscopy revealed that epoxidized soybean oil filled the lumen of the fibers completely or partially. Following increase of monomer to polymer conversion rate, in the incorporated modification with functionalized soybean oil, water absorption and dimensional changes were significantly reduced. Oil/monomer modification increased the surface hydrophobicity and droplet contact angle. Incorporated modification with raw oil and functionalized oil/styrene, improved the modulus of elasticity (MOE) of poplar wood samples compared to the control, but modulus of rupture (MOR) significantly increased only in one step modification with styrene. Hardness enhancement also was significant in modification with styrene and incorporated modification with portion of 10/90 epoxidized soybean oil/styrene.
Conclusion: In general, oil-containing (raw and epoxy) and two-step oil/styrene modified samples showed the best physical properties. In terms of mechanical properties, the samples containing polystyrene had the highest MOR, and incorporated styrene and oil modified samples, did not changed significantly compared to the control. The hardness of the samples modified merely with styrene and incorporation of 90% styrene/functionalized oil was significantly higher. Except for the elastic modulus and swelling, no significant differences were observed between properties of samples which were modified with integrated and two-step oil/styrene methods and the highest dimensional stability obtained in two-step modification.
کلیدواژهها [English]