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اصلاح چوب پالونیا بادی متیلول دی هیدروکسی اتیلناوره اصلاحشده (mDMDHEU) و بررسی تأثیر آن بر برخی ویژگیهای فیزیکی | ||
| تحقیقات علوم چوب و کاغذ ایران | ||
| مقاله 12، دوره 32، شماره 3 - شماره پیاپی 60، آبان 1396، صفحه 436-449 اصل مقاله (315.8 K) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22092/ijwpr.2017.110668.1415 | ||
| نویسندگان | ||
| محمد هادی رضوانی* 1؛ آیسونا طلائی2؛ حسینعلی رجبی چم حیدری3 | ||
| 1گروه علوم و تکنولوژی صنایع چوب، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی، تهران | ||
| 2عضو هیات علمی صنایع چوب، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی تهران، ایران | ||
| 3گروه علوم و تکنولوژی صنایع چوب، دانشکده مهندسی عمران، دانشگاه تربیت دبیر شهید رجایی تهران | ||
| چکیده | ||
| یکی از راهکارهای مهم افزایش گستره کاربرد اصلاح خواص چوب، بهرهگیری از گروههای عاملی فعال در ساختار چوب یا به اصطلاح آغشته کردن با ترکیبات N- متیلول است. هدف از این تحقیق، بررسی ویژگیهای فیزیکی چوب پالونیا پس از اصلاح با رزین دیوارهای Polycrease ECR، به نام دی متیلول دی هیدروکسی اتیلن اوره اصلاح شده (mDMDHEU) بود. نمونههای آزمون فیزیکی بر اساس استاندارد ASTM و EN تهیه گردیدند و به روش سلول تهی اصلاح شده در دو سطح غلظت 15 و 25 درصد از رزین اشباع شدند. پلیمریزاسیون رزین تحت اعمال دما در آون در بازه زمانی 24 ساعت، بهترتیب در دو سطح دمای 145 و 155 درجه سانتیگراد انجام شد. درصد افزایش وزن، تورم حجمی، جذب آب، واکشیدگی حجمی، اثر ضد واکشیدگی، آبشویی و زاویه تماس اندازهگیری شد. افزایش سطح غلظت mDMDHEU، به افزایش وزن و حجیمشدگی دیواره سلولی چوب منتهی شد. بیشترین درصد افزایش وزن (70/10 درصد) و ضریب حجیمشدگی (85/6 درصد) در سطح 25 درصد mDMDHEU، و دمای 145 درجه سانتیگراد تعیین شد. در مقایسه با چوب اصلاح نشده، ثبات ابعاد چوب اصلاح شده با mDMDHEU، در اثر افزایش سطح جذب پلیمر، بهبود یافته و جذب آب کاهش داشته است، بهطوریکه بیشترین پایداری ابعاد در سطح حاوی 25 درصد mDMDHEU، و دمای 145 درجه سانتیگراد اندازهگیری شد. بهعلاوه تیمار mDMDHEU، به آبشویی مقاوم بود. اندازهگیری زاویه تماس، بهبود آبگریزی چوب پس از اصلاح را تأیید کرد. اصلاح با mDMDHEU، بهبود معنیدار خواص فیزیکی را بههمراه داشت. بهبود مقاومت فیزیکی چوب اصلاح شیمیایی شده را میتوان بهکاهش رطوبت، حجیمشدن دیواره سلولی و مسدود شدن منافذ در اثر واکنشپذیری بالای mDMDHEU، با پلیمر دیواره سلول چوب نسبت داد. | ||
| کلیدواژهها | ||
| ویژگی های فیزیکی؛ (Polycrease ECR (mDMDHEU؛ چوب پلیمر دیوارهای؛ جذب آب؛ ضریب حجیم کنندگی | ||
| عنوان مقاله [English] | ||
| Modification of Paulownia Wood with methylolated dimethyloldihydroxyethylenurea (mDMDHEU) and the investigation of its effect on Some of Strength Properties | ||
| نویسندگان [English] | ||
| Mohammad Hadi Rezvani1؛ Aisona Talaei2؛ Hosseinali Rajabi Cham Heidari3 | ||
| 1Wood Science and Technology Department, Faculty of Civil Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran | ||
| 2Wood Science and Technology Department, Faculty of Civil Engineering, shahid Rajaee Teacher Training University, Tehran, Iran | ||
| 3Wood Science and Technology, Faculty of Civil Engineering, University of Shahid Rajaee Teacher Training, Tehran, Iran | ||
| چکیده [English] | ||
| One of the main strategies to develop the extent of wood modification is using active functional groups in wood structure or the so-called impregnation with modified N-methylol compound. The aim of this study was to evaluate the physical properties of paulownia wood after modify with Polycrease ECR Cell wall resin, to name modified dimethylol-dihydroxyethyleneurea (mDMDHEU). Physical test samples were prepared according to ASTM and EN standard and treated with pressure vessel method at two concentration levels; 15 and 25 percent of soluble resin. For polymerization, treated samples were heated in oven for 24-hour periods at 145 and 155 ºC respectively. Weight percent gain (WPG), bulking, water soaking, swelling, anti-swelling efficiency (ASE), leaching and contact angle were determined. High mDMDHEU concentration increased the weight gain and cell wall bulking. Highest weight percent gain (10.70%) and bulking efficiency (6.85%) in to levels of 25% were determined at 155 ˚C. In comparison with the unmodified wood, the mDMDHEU modified wood due to absorbed polymer enhancement exhibited improved dimensional stability and reduced water uptake, and maximum dimensional stability were determined in samples modified using to level 25% mDMDHEU containing solutions and curing temperature 155 ºC. Moreover, mDMDHEU treatment was resistant to leaching. Contact angle measurement further confirmed the improved hydrophobicity of wood after modification. Modification with mDMDHEU improved significantly the physical properties. The improve of the resistance of chemically modified wood exposed to can be attributed to the reduction of wood moisture, bulking of cell walls and cell cavities blocking affect to dominant reactivity mDMDHEU with cell wall wood polymer. | ||
| کلیدواژهها [English] | ||
| physical properties, Polycrease ECR (mDMDHEU), Cell Wall WPC, water absorption, bulking efficiency | ||
| مراجع | ||
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