Ảnh hưởng của nhiệt độ và thời gian phản ứng đến một số thông số kỹ thuật keo phenol formaldehyde phân tử lượng thấp và thử nghiệm biến tính gỗ cao su bằng phương pháp polymer hóa=Effect of temperature and reaction time on some technical parameters of low molecular weight Phenol Formaldehyde resin and testing 113of Hevea brasiliensis modification by polymerization method

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Tác giả: Thế Mạnh Phạm

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Khoa học và Công nghệ Lâm nghiệp, 2024

Mô tả vật lý: tr.113-120

Bộ sưu tập: Metadata

ID: 253098

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Bài báo này trình bày nghiên cứu ảnh hưởng của nhiệt độ và thời gian phản ứng đến các tính chất của keo phenol-formaldehyde phân tử lượng thấp (LWPF) và khả năng ứng dụng trong biến tính gỗ cao su. Các chỉ tiêu như độ nhớt, hàm lượng khô, độ tan trong nước và thời gian đóng rắn của keo PF đã được xác định thông qua các thí nghiệm đa yếu tố. Kết quả cho thấy độ nhớt của keo LWPF dao động từ 47-63 m.Pa.s và có xu hướng tăng khi nhiệt độ và thời gian phản ứng tăng. Hàm lượng khô của keo biến động từ 5,13% đến 56,2%, trong khi độ tan trong nước giảm từ 5,6 xuống 3,0 khi điều kiện phản ứng thay đổi. Thời gian đóng rắn của keo LWPF dao động từ 284-342 giây, với mối tương quan mạnh mẽ giữa nhiệt độ, thời gian phản ứng và các tính chất này. Chất lượng gỗ cao su sau khi được xử lý bằng dung dịch keo PF phân tử lượng thấp và sấy ở nhiệt độ cao đã cải thiện rõ rệt. Khối lượng gỗ tăng trung bình 29,5%, trong khi thể tích gỗ tăng 6,3%, độ hút nước khoảng 67,3%, độ trương nở chiều dày khoảng 4,5%. Các kết quả này chỉ ra rằng keo LWPF đã thâm nhập vào các khoảng trống và vách tế bào gỗ, giúp nâng cao khả năng chịu nước và giảm độ trương nở của gỗ. Nghiên cứu cung cấp cơ sở dữ liệu quan trọng cho việc tổng hợp keo PF phân tử lượng thấp và ứng dụng phương pháp ngâm tẩm kết hợp polymer hóa bằng quá trình sấy nhiệt độ cao trong biến tính gỗ cao su.This paper presents a study on the influence of temperature and reaction time on the properties of low molecular weight phenol-formaldehyde (LWPF) resin and its application in the modification of rubberwood (Hevea brasiliensis). Technical properties of the LWPF resin such as viscosity, solid content, water solubility, and curing time were determined through multifactorial experiments. The results show that the viscosity of the LWPF resin ranged from 47 to 63 m.Pa.s and tended to increase as temperature and reaction time increased. The solid content of the resin varied from 5.13% to 56.2%, while water solubility decreased from 5.6 to 3.0 as reaction conditions changed. The curing time of the LWPF resin ranged from 284 to 342 seconds, with a strong correlation between temperature, reaction time, and these properties. The quality of rubberwood treated with the LWPF resin solution and subjected to high-temperature curing improved significantly. The average wood mass increased by 29.5%, while the wood volume increased by 6.3%, water absorption was about 67.3%, and thickness swelling was approximately 4.5%. These results indicate that the LWPF resin infiltrated the lumens and cell walls of the wood, enhancing its water resistance and reducing its swelling. The study provides valuable data for synthesizing low molecular weight phenol-formaldehyde resin and applying the impregnation method combined with polymerization through high-temperature curing in rubberwood modification

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