2005 Fiscal Year Final Research Report Summary
Polyurethane derivatives from sodium lignosulfonate
| Project/Area Number |
16580137
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林産科学・木質工学
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| Research Institution | Fukui University of Technology |
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Principal Investigator |
HATAKEYAMA Hyoe Fukui University of Technology, Faculty of Engineering, Professor, 工学部, 教授 (20271611)
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| Project Period (FY) |
2004 – 2005
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| Keywords | sodium lignosulfonate / diethylene glyco / triethylene glycol / polyethylene glycol / polyurethane / glass transition temperature / thermal degradation / mechanical properties |
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| Research Abstract |
Sodium lignosulfonate (LS) was obtained as a by-product of sulfite pulping process. LS has not been used as a chemical component of standard lignin-based polymers such as epoxy resins due to its ionic nature. However, in this research, LS was dissolved in some kinds of solvent such as diethylene glycol (DEG), triethylene glycol (TEG) and polyethylene glycol (PEG,M_w=ca.200). LS-based polyurethane (PU) foams (LSPU) were prepared using the above DEG, TEG and PEG solutions of LS. The thermal and mechanical properties of rigid LSPU foams were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG).
In order to prepare PU foams, LS was first dissolved in DEG, TEG or PEG. The above solutions with various LS contents were mixed with small amounts of silicon surfactant, catalyst and water. This premixture was reacted with polyphenylene methylene polyisocyanate (MDI). PU foams obtained from the above three kinds of lignin-based oligo- and poly-ethylene glycols (DEG,TEG
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and PEG) were designated as LSDPU,LSTPU and LSPPU, respectively. Glass transition temperatures (T_g's) of LSDPU and LSTPU increased slightly with increasing LS content. However, T_g of LSPPU increased obviously with increasing LS content, since the rigid phenyl propane structure in LS acts as a hard segment efficiently in PU networks containing long oxyethylene chains of PEG such as in the case of LSPPU. On the other hand, it is considered that LS molecules in LSDPU and LSTPU do not effectively influence the motion of the PU molecules, since DEG and TEG components in LSDPU and LSTPU have shorter oxyethylene molecular chains than PEG components in LSPPU, which restrict effectively the motion the PU network in the same way as LS components. Two step thermal degradations were clearly observed in thermogravimetry (TG) curves of the above PU's. Thermal degradation temperature (T_<d1>) observed at low temperature side (ca. 300℃) did not change markedly with increasing LS content, which was attributed to the dissociation of urethane bonding between the phenolic hydroxyl group and the isocyanate group. T_<d2> which was observed at high temperature side (ca. 380℃), were attributed to the thermal degradation of urethane bonding between the alcoholic hydroxyl group and the isocyanate group. With increasing LS content, compression strength at 10 % strain (σ_<10>) of LSPPU increased while σ_<10> of LSDPU and LSTPU slightly decreased. Mechanical properties of PU foams were markedly affected by the apparent density (p) of PU's. The apparent density can be controlled by foaming conditions. This obviously contributes the control of mechanical properties that are important as practical properties of PU foams. Less
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Research Products
(8 results)
