On the Feasibility of a pMDI-Reduced Production of Wood Fiber Insulation Boards by Means of Kraft Lignin and Ligneous Canola Hulls.

Kolja Ostendorf,Markus Euring,Jean Lawrence Tene Tayo,Arne Beulshausen,Christian Ahrens

doi:10.3390/polym13071088

Kolja Ostendorf, Markus Euring + Show 3 more

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https://doi.org/10.3390/polym13071088

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Journal: Polymers	Publication Date: Mar 30, 2021
Citations: 11	License type: CC BY 4.0

Affiliation: University of Göttingen

Abstract

The thermal insulation of buildings using wood fiber insulation boards (WFIBs) constitutes a positive contribution towards climate change. Thereby, the bonding of wood fibers using mainly petrochemical-based resins such as polymeric diphenylmethane diisocyanate (pMDI) is an important measure to meet required board properties. Still there is a need to reduce or partial substitute the amount of these kinds of resins in favor of a greener product. This study therefore focusses on the feasibility of reducing the amount of pMDI by 50% through the addition of 1% BioPiva 395 or Indulin as two types of softwood Kraft-Lignin and lignin rich canola hulls together with propylene carbonate as a diluent. A panel density of 160 kg/m3 and a thickness of 40 mm was aimed. The curing of these modified pMDI was investigated by using two types of techniques: hot-steam (HS) and innovative hot-air/hot-steam-process (HA/HS). The WFIBs were then tested on their physical-mechanical properties. The equilibrium moisture content (EMC) was determined at two different climates. An exemplary investigation of thermal conductivity was conducted as well. The WFIBs did undergo a further chemically based analysis towards extractives content and elemental (C, N) composition. The results show that it is feasible to produce WFIBs with lower quantities of pMDI resin and added lignin with enhanced physical-mechanical board properties, which were lacking no disadvantages towards thermal conductivity or behavior towards moisture, especially when cured via HA/HS-process.

Highlights

The use of wood fiber insulation boards (WFIBs) is an illustrative example for the positive contribution towards climate change
The polymeric diphenylmethane diisocyanate (pMDI) (2%) was mixed together with propylene carbonate at a ratio of 1 to 1, which enhanced the viscosity on the one hand, and made it possible to add 1% of lignin or lignin rich canola hulls as additives on the other hand
The addition of BioPiva 395 (BP), Indulin AT (IN) or Canola Hull (CH) had no measurable influence on the lignin content

Summary

Introduction

The use of wood fiber insulation boards (WFIBs) is an illustrative example for the positive contribution towards climate change. Lignin is one of the most abundant natural resources in the world, accounting for 30% of the quantitative most relevant re-growing resources [14,15,16] It is formed by an enzymemediated dehydrogenative polymerization of three different types of phenylpropanoid units (monolignols) to an amorphous, polyphenolic biopolymer [17]. There are actual studies, utilizing natural resources as lignosulfonate as well as tannin [31] together with pMDI as crosslinking agent Another approach is to use lignin containing cellulose nanofibrils to enhance the performance of pMDI [32] or rather partially substitute pMDI [33]. The resin cure is realized by using two different techniques: first by using hot-steam and, second, by using innovative hot-air/hot-steamprocess (HA/HS) invented by Euring and Kharazipour [37]

Materials and Methods

Thermal Conductivity and Equilibrium Moisture Content

Physical-Mechanical Panel Properties

Chemical Material Analysis

Elemental Analysis

Thermal Conductivity

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