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Utilization of Kraft Softwood Lignin...

Du, Jing.

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Utilization of Kraft Softwood Lignin in Phenol Formaldehyde Adhesives and Phenolic Foams.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Utilization of Kraft Softwood Lignin in Phenol Formaldehyde Adhesives and Phenolic Foams./
作者:	Du, Jing.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2018,
面頁冊數:	163 p.
附註:	Source: Dissertation Abstracts International, Volume: 79-12(E), Section: B.
Contained By:	Dissertation Abstracts International79-12B(E).
標題:	Wood sciences. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10969782
ISBN:	9780438282971

Utilization of Kraft Softwood Lignin in Phenol Formaldehyde Adhesives and Phenolic Foams.
Du, Jing.

Utilization of Kraft Softwood Lignin in Phenol Formaldehyde Adhesives and Phenolic Foams. - Ann Arbor : ProQuest Dissertations & Theses, 2018 - 163 p.

Source: Dissertation Abstracts International, Volume: 79-12(E), Section: B.

Thesis (Ph.D.)--North Carolina State University, 2018.

The work presented here focuses on utilization of kraft softwood lignin in phenol formaldehyde (PF) resins and phenolic foams. Enormous efforts have been carried out to find promising substitution of phenol and reduce the dependence of this industry on petroleum industry. Due to the low cost and sustainability, as well as the structural similarity with phenol formaldehyde resin, lignin has been considered as one of the promising candidates (El Mansouri & Salvado, 2006). However, direct use of lignin in the production of phenolformaldehyde (PF) resins was limited given the much lower reactive sites of lignin in comparison to conventional phenols (Hu, Pan, Zhou, & Zhang, 2011). Most research findings indicate a successful substitution up to 25% of phenol with kraft lignin in PF resin production without compromising the bonding properties of resins (Aierbe, Echeverrya, Riccardi, & Mondragon, 2002).

ISBN: 9780438282971Subjects--Topical Terms:

3168288
Wood sciences.

Utilization of Kraft Softwood Lignin in Phenol Formaldehyde Adhesives and Phenolic Foams.
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245 1 0 $a Utilization of Kraft Softwood Lignin in Phenol Formaldehyde Adhesives and Phenolic Foams.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2018
300 $a 163 p.
500 $a Source: Dissertation Abstracts International, Volume: 79-12(E), Section: B.
500 $a Advisers: Hasan Jameel; Hou-min Chang.
502 $a Thesis (Ph.D.)--North Carolina State University, 2018.
520 $a The work presented here focuses on utilization of kraft softwood lignin in phenol formaldehyde (PF) resins and phenolic foams. Enormous efforts have been carried out to find promising substitution of phenol and reduce the dependence of this industry on petroleum industry. Due to the low cost and sustainability, as well as the structural similarity with phenol formaldehyde resin, lignin has been considered as one of the promising candidates (El Mansouri & Salvado, 2006). However, direct use of lignin in the production of phenolformaldehyde (PF) resins was limited given the much lower reactive sites of lignin in comparison to conventional phenols (Hu, Pan, Zhou, & Zhang, 2011). Most research findings indicate a successful substitution up to 25% of phenol with kraft lignin in PF resin production without compromising the bonding properties of resins (Aierbe, Echeverrya, Riccardi, & Mondragon, 2002).
520 $a This thesis is divided into four chapters. In Chapter 2, kraft lignin (KL) was applied to synthesize KL-based phenol formaldehyde resins at 25%, 38% and 50 wt.% substitution rates. Results showed that up to 25% of substitution rate can be achieved with kraft lignin without significant sacrifice of shear strength and wood failure. Higher substitution rate was limited due to the lower reactivity and higher molecular weight of kraft lignin. In order to tune the lignin structure for further utilization in phenol formaldehyde resins, kraft lignin was phenolated with the catalyst of sulfuric acid. Phenolation proved to not only improve the reactivity of lignin towards formaldehyde but also lower the molecular weight and tune the lignin structure. With the improved reactivity of phenolated lignin (PL), formaldehyde amount needs to be adjusted according to the potential reactive sites. After adjustment, PLPF resins with 38% substitution for phenol proved to be possible with comparable bonding strength after formaldehyde amount adjustment. However, the wood failure and shelf-life of PLPF did not meet the requirement for exterior wood products.
520 $a To further improve the shelf-life and wood failure performance of lignin-based PF resins, Chapter 3 studied the protocol parameters and optimized the protocol of resin preparation. The parameters investigated include the formaldehyde addition method; F/P ratio as well as reaction temperature and time. The results showed that split formaldehyde addition method worked promisingly to maintain the mechanical properties and also give a longer shelflife. An F/P ratio of 1.9:1 resulted in the best mechanical performance for 38% PLPF. In addition, with a lower reaction temperature and longer reaction time, resins with improved shelf-life and comparable shear strength can be obtained. The optimal conditions for 38% PLPF resols were established as 75°C-6hr and 80°C-4hr15min with the split addition method. Results showed that a 42%-45% reduction in resol viscosities was observed while comparable shear strengths were maintained with the optimized protocol.
520 $a Besides the incorporation of lignin in phenol formaldehyde resins, lignin-based phenolic foams have also been investigated in Chapter 4 and 5. In Chapter 4, both kraft lignin and phenolated lignin-based phenolic foams were prepared and characterized. Pure phenolic foam was synthesized as reference. Results indicate that improved physical properties and better thermal performances were observed when phenolated lignin was applied. A substitution rate of 10 wt.% can be achieved with kraft lignin while lignin-based phenolic foams were successfully prepared with by substitution phenol up to 20 wt.% with phenolated lignin.
520 $a The effect of various parameters on the mechanical properties and thermal performances have been investigated in Chapter 5. Experimental designs were employed to study the formulation of KLPF and PLPF foam productions. With unmodified KL, only 10% of phenol can be replaced to ensure comparable mechanical properties with a highly restrictive reaction conditions. However, by using PL, a substitution rate as high as 20% can be achieved under various reaction conditions, which gives more flexibility in terms of end-use requirement.
520 $a Aimed at further understanding the factors that were related to the properties, fundamental studies were carried out in terms of the degree of crosslinking and pore sizes. Studies revealed the linear correlation between the degree of crosslinking and log (Gamma), in which Gamma is the final single response of mechanical properties. As to the effect of pore sizes, with the incorporation of lignin, larger pore size and more dispersed size distribution was observed. Meanwhile, similar average pore sizes were observed for both 10%PLPF and 20%PLPF foams. The degree of crosslinking was identified as one of the most crucial factors influencing the final mechanical properties of produced foams.
590 $a School code: 0155.
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710 2 $a North Carolina State University. $b Forest Biomaterials. $3 3173239
773 0 $t Dissertation Abstracts International $g 79-12B(E).
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791 $a Ph.D.
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793 $a English
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