ارزیابی رفتار و روند جذب آب و واکشیدگی ضخامت تخته فیبر نیمه سنگین(MDF) ساخته شده از الیاف تیمار شده با روش گرمآبی

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد علوم و صنایع چوب وکاغذ، دانشگاه تربیت مدرس

2 دانشیار گروه علوم و صنایع چوب وکاغذ، دانشگاه تربیت مدرس

چکیده

در این پژوهش، رفتار جذب آب و واکشیدگی ضخامت تخته فیبر نیمه سنگین (MDF)  ساخته شده از الیاف تیمار شده به روش گرمآبی مورد بررسی قرار گرفت. بدین منظور الیاف در درون آب و در سه سطح دمای 120، 150 و 180 درجه سلسیوس و مدت زمان تیمار در سه سطح ماندگاری 0، 30 و 90 دقیقه در رآکتور ویژه اصلاح چوب و مواد لیگنوسلولزی تیمار شدند. تخته‌های آزمونی با تراکم پایه 7/0 گرم بر سانتی‌متر مکعب و با چسب اوره فرم آلدهید (10% بر پایه وزن خشک الیاف) و با بهره‌گیری از پرس گرم (با دمای 175 درجه سلسیوس)، تحت فشار پرس  30 بار و به مدت 5 دقیقه ساخته شدند. سپس از تخته‌ها، نمونه-های آزمونی به ابعاد 10×20×20 میلی‌متر تهیه و پس از خشک شدن در اون و توزین، در آب غوطه ور شدند و رفتار و روند جذب آب همراه با رفتار و روند واکشیدگی ضخامت تعیین شدند. نتایج نشان دادند که با افزایش دمای تیمار (به جز نمونه های تیمار شده در دمای 120 درجه سلسیوس)، میزان جذب آب و واکشیدگی تخته‌ها به طور قابل توجهی کاهش می‌یابند؛ در حالی که در یک سطح دمایی مشخص، افزایش زمان ماندگاری تاثیر قابل‌توجهی بر جذب آب ندارد؛ ولی افزایش دما تأثیرگذارتر است.
 

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