Authors: Tang Mengfei; Wang Mingjie; Chen Yao *; Gao Jianmin
(School of materials science and technology, Beijing Forestry University, Key Laboratory of wood materials science and application, Ministry of education, Beijing 100083)
Author(s): TANG Meng-fei; WANG Ming-jie; CHEN Yao*; GAO Jian-min
(College of Materials Science and Technology,Key Laboratory of Wood Material Science and Utilization of Ministry of Education,Beijing Forestry University,Beijing 100083,China)
Key words: lignin, HDPE, composites, anhydrides, physical and mechanical properties
Keywords:lignin; high density polyethylene; composite material; anhydride; mechanical property
Classification No.: s781.2
DOI:10.3969/j.issn.1001-7461.2020.02.30
Abstract:
In this study, maleic anhydride (MA), succinic anhydride (SA), phthalic anhydride (PA) were used to modify kraft lignin (KL) and KL / HDPE composites were prepared by injection molding. The compatibility of the modified kl-hdpe composite was simulated by compatibility analysis. The water absorption and thickness expansion of the composite were analyzed. The MOE and MOR of the composite were characterized by three-point bending. The results show that the interface compatibility of the composite is improved after modification. Compared with the KL modified by PA, the KL modified by Ma and SA has better interface compatibility with HDPE. The moisture absorption rate of the modified lignin HDPE composite decreased, and the size stability of moisture absorption increased. The water absorption rate of PA modified lignin HDPE composite is higher than that of unmodified lignin HDPE Composite in the first 500 hours, but it is higher than that of unmodified lignin HDPE Composite in the last 500 hours. Among them, ma-pe modified composite has better water resistance and moisture absorption dimensional stability. The MOE of lignin HDPE composite modified by Ma, SA and PA increased by 71%, 42% and 17%, respectively. Ma, SA and PA can remove most of the hydroxyl groups in lignin and reduce the hydrophilicity of lignin. After modification, the MOR of the composite increased, especially that of the Ma modified KL composite.
Abstract:
Industrial alkali lignin (Kraft lignin) is widely derived from pulping black liquor,which has broad commercial using prospects.However,the high polarity of Kraft lignin (KL) makes it difficult to compound with HDPE.In this study,maleic anhydride (MA),succinic anhydride (SA), and phthalic anhydride (PA) were employed to modify KL.The modified KL/HDPE composite was manufactured using injection molding method.The compatibility of KL-HDPE composites was simulated by compatibility analysis.The water absorption and water swelling rate of the composites were analyzed.The modulus of elasticity (MOR) and modulus of rupture (MOE) of the composites were characterized by three-point bending.The results showed that the interfacial compatibility of the modified composites was improved.Compared with PA modified KL, MA or SA modified KL showed good interfacial compatibility with HDPE.The lignin-HDPE composite modified by MA or SA had reduced water absorption and improved moisture absorption dimensional stability.The PA-modified lignin-HDPE composite showed a little higher water absorption in the first 500 hours,but its water absorption was lower than that of the unmodified lignin-HDPE composite after 500 hours’ soak.The composites manufactured with MA modified KL exhibited better water resistance and hygroscopic dimensional stability.The MOE of MA,SA,PA modified lignin-HDPE composite were significantly improved (71%,42%,and 17%,respectively).The modification could remove most of the hydroxyl groups in lignin,and the hydrophilicity of lignin was reduced as a result.The MOR of the modified composite increased.The strength increased significantly when composited prepared with MA modified KL.
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