تاثیر نوع، اندازه و درصد الیاف بر دانسیته و قدرت نگهداری اتصال دهنده‌ها در چندسازه الیاف طبیعی–پلاستیک ساخته شده به روش خشک

نویسندگان

1 دانشیار دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

2 دانشجوی دکتری دانشگاه علوم کشاورزی و منابع طبیعی گرگان، ایران

3 دانشیار دانشگاه علوم کشاورزی و منابع طبیعی ساری، ایران

چکیده

در این پژوهش اثر نوع، اندازه و درصد الیاف بر دانسیته و قدرت نگهداری اتصال دهنده (میخ و پیچ) در چندسازه الیاف طبیعی-پلاستیک ساخته شده با روش اختلاط خشک مورد بررسی قرار گرفت. تخته‌های چوب-پلاستیک با دانسیته اسمی 1 گرم بر سانتیمتر مکعب و با ابعاد 30×20×1 سانتی‌متر ساخته شدند. از پلی‌پروپیلن (PP) به عنوان فاز زمینه و از الیاف چوب صنوبر و الیاف کاه برنج (به صورت آرد) به عنوان تقویت‌کننده و 4 درصد مالئیک انیدرید پلی‌پروپیلن (MAPP) به عنوان جفت‌کننده استفاده شد. مقدار الیاف استفاده شده 45، 60 و 75 درصد بر اساس وزن خشک تخته در دو اندازه40-20 مش و60-40 مش بود. در مجموع 12 تیمار و از هر تیمار 3 تخته به صورت اختلاط خشک و با استفاده از پرس گرم ساخته، سپس اندازه‌گیری دانسیته، قدرت نگهداری میخ و پیچ انجام شد. نتایج نشان داد با افزایش درصد الیاف، دانسیته تخته‌ها کاهش یافته، نمونه‌های دارای الیاف کوچکتر (60-40 مش) دانسیته بالاتری دارند. همچنین نمونه‌های دارای الیاف چوب صنوبر در مقایسه با نمونه‌های دارای الیاف کاه برنج، قدرت نگهداری اتصال دهنده بالاتری داشتند و با افزایش درصد الیاف، مقادیر آن برای هر دو نوع الیاف کاهش پیدا کرد. همچنین، نتایج حاکی از آن است که قدرت نگهداری اتصال دهنده برای نمونه‌های دارای الیاف ریزتر، بزرگتر است، هرچند، تاثیر این موضوع وابسته به درصد الیاف بوده که در مقادیر بالاتر الیاف نامحسوس است.

کلیدواژه‌ها


عنوان مقاله [English]

Effect of fiber content, size and type on board density and withdrawal strength of fasteners in natural fiber-plastic composites made through dry process

نویسندگان [English]

  • a a 1
  • w w 2
  • x x 3
1
2
3
چکیده [English]

In this study, the effects of fiber content, type and size on board density and withdrawal strength of fasteners (nailed and screwed) in joints made in natural fibers-plastic composites produced through a dry process were investigated. Wood-plastic boards were made at a nominal density of 1 g/cm3 and dimensions of 30×20×1 cm. Polypropylene (PP) as the matrix and poplar wood fiber and rice straw fibers as the reinforcement were used together with 4% (based on weight) maleic anhydride grafted polypropylene (MAPP) as the coupling agent. Three levels of dry poplar and rice straw fibers, namely 45%, 60%, and 75% based on the composition by weight at two particle sizes of 20-40 mesh and 40-60 mesh were mixed with PP. Totally, 12 formulations with 3 replications were considered. The final composites were made by pressing the prepared mats between the hot plates of a compression press by employing combinations of temperature and pressure in three stages. After storing the composites at room temperature for 15 days, the density of the boards and withdrawal strength of fasteners were measured. The results showed that fiber content may significantly influence the density of the samples and the fiber size of 40–60 mesh may lead to a higher density. In addition, it was found that poplar fibers (the type of fiber) results in higher withdrawal strength of fastener in the composites than rice straw fibers. Furthermore, the withdrawal strength of fasteners was reduced as the fiber content was increased. However, this effect is dependent...

کلیدواژه‌ها [English]

  • Density
  • Polypropylene
  • poplar
  • rice straw
  • withdrawal strength
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