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Cellulose fiber based fungal and water resistant insulation materials
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.ORCID iD: 0000-0002-2272-5067
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.ORCID iD: 0000-0002-7055-1057
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.ORCID iD: 0000-0002-1656-1465
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Wood Chemistry and Pulp Technology.
2017 (English)In: International Journal of the Biology, Chemistry, Physics, and Technology of Wood, E-ISSN 1437-434XArticle in journal (Refereed) Epub ahead of print
Abstract [en]

The development of thermal insulation materials from sustainable, natural fibrous materials is desirable.In the present study, cellulose fiber based insulation foams made of bleached chemi thermo mechanical pulp(CTMP) have been investigated. To improve water resistance, the foams were impregnated with hydrophobic extractives from the outer bark of birch (Betula verrucosa)and dried. The surface morphology of the foams and the distribution of the deposited particles from the extractives were observed by scanning electron microscopy (SEM).The modified foams showed improved water resistance, as they did not disintegrate after immersion in water for7 days, whereas the unmodified foam did. Compared to the unmodified foam, the modified foams absorbed 50%less moisture within 24 h. The modification had no negative effects on the thermal insulation properties, fungal resistance or compressive strength of the foams. The proposed approach is simple and can be easily integrated into plants working based on the biorefinery concept.

Place, publisher, year, edition, pages
Berlin, Germany: Walter de Gruyter, 2017.
Keywords [en]
biorefinery; birch bark; cellulose; fungal resistance; insulation; water resistance
National Category
Wood Science Paper, Pulp and Fiber Technology
Research subject
Fibre and Polymer Science
Identifiers
URN: urn:nbn:se:kth:diva-205367DOI: 10.1515/hf-2016-0162ISI: 000404721500013Scopus ID: 2-s2.0-85023159213OAI: oai:DiVA.org:kth-205367DiVA, id: diva2:1088761
Projects
Energy-efficient cellulosic insulation products/panels for green building solutions
Funder
Swedish Research Council Formas
Note

QC 20170424

Available from: 2017-04-14 Created: 2017-04-14 Last updated: 2018-11-12Bibliographically approved
In thesis
1. Cellulose-fiber-based thermal insulation materials with fungal resistance, improved water resistance and reaction-to-fire properties
Open this publication in new window or tab >>Cellulose-fiber-based thermal insulation materials with fungal resistance, improved water resistance and reaction-to-fire properties
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Thermal insulation materials made from natural fibrous materials, such as cellulose fibers, have advantages over others from a sustainability point of view. However, cellulosic materials are generally prone to mold and absorb moisture, and these have negative effects on the insulation properties, the durability of insulation materials, and interior air quality. In this thesis, cellulose-fiber-based insulation foams were prepared from bleached chemithermomechanical softwood pulp, and these foams showed promising thermal insulation properties and fungal resistance. Hydrophobic extractives were isolated from birch (Betula verrucosa) outer bark and used to improve the water resistance of the foams, which were impregnated in solutions of extractives and then dried. The modified foams showed greater water resistance, and the modification had no negative effects on the thermal insulation, fungal resistance, and compressive strength of the foams.

Another potential problem with low density cellulosic thermal insulation materials is their poor reaction-to-fire properties. Cellulose-fiber-based insulation foams were prepared from formulations containing bleached chemithermomechanical softwood pulp and commercial fire retardants to improve the reaction of the foams to fire. Single-flame source test results showed that the foams containing 20% expandable graphite (20% EG) or 25% synergetic (25% SY) fire retardant had significantly improved reaction-to-fire properties and passed class E, which reflected that they can resist a small flame attack without substantial flame spreading for a short period according to EN 13501-1. Compared with the reference without any fire retardant, the peak heat release rate (Peak-HRR) of the 20% EG and 25% SY decreased by 62% and 39% respectively when the samples were subjected to a radiance heat flow of 25 kW m-2 in a Cone Calorimeter.

The thesis demonstrates that it is possible to produce cellulose-fiber-based insulation materials with improved properties in terms of fungal, improved water resistance and reaction-to-fire properties.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2017. p. 37
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 2017:19
Keywords
biorefinery, birch bark, cellulose, reaction-to-fire properties, fungal resistance, thermal insulation, water resistance
National Category
Wood Science Paper, Pulp and Fiber Technology
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-205608 (URN)978-91-7729-330-9 (ISBN)
Presentation
2017-05-24, Rånbyrummet, Teknikringen 56, KTH, Stockholm, 10:00 (English)
Opponent
Supervisors
Projects
Energy-efficient cellulosic insulation products/panels for green building solutions
Funder
Swedish Research Council Formas
Note

QC 20170428

Available from: 2017-04-28 Created: 2017-04-25 Last updated: 2017-04-28Bibliographically approved
2. Cellulosic Thermal Insulation with Improved Water Resistance and Fire Retardancy
Open this publication in new window or tab >>Cellulosic Thermal Insulation with Improved Water Resistance and Fire Retardancy
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Sweden is one of the largest countries by area in Europe, and almost 70% of it is covered by forest. These abundant forest resources benefit the Swedish bioeconomy, but the pulp and paper industry is facing the challenge of a decrease in the demand for printing paper due to a significant shift to electronic media; therefore, it is a priority to use pulp to produce alternative value-added products, such as thermal insulating materials in buildings. Cellulosic thermal insulation can reduce the heating energy consumption of buildings, and decrease the emission of CO2, thus contributing to a sustainable society.

However, cellulosic thermal insulation needs to overcome its poor water resistance, to lower the risk of fungi and ensure a good interior air quality. In the work described in this thesis, cellulosic insulation materials have been produced from pulp fibers, water, and foaming agent by a foam-forming technique. Hydrophobic extractives isolated from birch outer bark were used to functionalize the insulating materials. These materials showed an improved water resistance due to the intrinsic non-polarity of the extractives, promising thermal insulation properties and fungal resistance.

Fire retardancy is another challenge for cellulosic thermal insulation, and cellulosic insulation materials were here prepared from formulations containing pulp and commercial fire retardants. Fire test results showed that the materials containing 20% expandable graphite or 25% synergetic fire retardant had a significantly improved fire retardancy, being able to resist a small flame attack for a short period without substantial flame spreading. A study of the mechanism of fire retardancy confirmed that the fire retardants can catalyze the dehydration of pulp and promote the generation of a protective char layer that prevents the materials from further decomposition.

Bio-based fire-retardant coatings such as sulfonated kraft lignin and nanoclay can provide a more efficient fire-retardant protection on the cellulosic insulation than a fire retardant incorporated in the materials. A nanoclay coating performed the best because of its very good thermal stability. The effective bio-based fire-retardant coating is promising for future use in cellulosic thermal insulation materials.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2018. p. 59
Series
TRITA-CBH-FOU ; 2018:29
Keywords
Bio-based, Cellulosic, Fire retardant, Thermal insulation
National Category
Paper, Pulp and Fiber Technology Wood Science
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-233516 (URN)978-91-7729-864-9 (ISBN)
Public defence
2018-09-14, K1, Teknikringen 56, KTH Campus, Stockholm, 10:00 (English)
Opponent
Supervisors
Projects
Energy-efficient cellulosic insulation products/panels for green building solutions
Funder
Swedish Research Council Formas
Note

QC 20180821

Available from: 2018-08-21 Created: 2018-08-21 Last updated: 2018-08-21Bibliographically approved
3. Antimicrobial materials from cellulose using environmentally friendly techniques
Open this publication in new window or tab >>Antimicrobial materials from cellulose using environmentally friendly techniques
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The transition to a more biobased society introduces both new opportunities and new challenges as we replace nonrenewable materials with renewable alternatives. One important challenge will be to control microbial growth on materials, both to protect the materials from biological degradation and to prevent the spread of infections and toxins that can cause illness.

In this thesis, both existing and new types of cellulose-based materials were treated with environmentally friendly alternatives to usual biocides to prevent microbial growth and remove bacteria from water. Two types of antimicrobial systems were studied, and the antimicrobial effects were evaluated for bacteria and fungi using both model organisms and wild-type cultures.

The first antimicrobial approach employed was a nonleaching and contact-active layer-by-layer adsorption of polyelectrolytes to provide the cellulose fibers with a cationic surface charge, which attracts and captures bacteria onto the fiber surface. The study showed that paper filters with pores much larger than bacteria could remove more than 99.9 % of E. coli from water when used in filtration mode. The polyelectrolyte-modified materials showed a good antibacterial effect but did not prevent fungal growth.

The second approach was to utilize biobased compounds with antimicrobial properties, which were applied to cellulose fiber foam materials. Chitosan and extractives from birch bark were selected as biobased options for antimicrobial agents. Two types of cellulose fiber foam materials were developed and evaluated for their antimicrobial properties.

This thesis shows the importance of understanding both the application and the targeted microorganism when selecting an environmentally friendly antimicrobial system for treating biobased materials. It highlights that a good understanding of both material science and microbiology is important when designing new antimicrobial materials.

Abstract [sv]

Satsningen på ett mer biobaserat samhälle, där vi ersätter icke-förnybara material med förnyelsebara alternativ, är en pusselbit för en mer hållbar framtid samtidigt som den medför nya utmaningar. En viktig uppgift är att minska och kontrollera mikrobiell tillväxt, både för att skydda material från biologisk nedbrytning men också för att förhindra spridning av infektioner och toxiner.

Cellulosabaserade material har behandlats med miljövänliga alternativ till traditionella biocider för att förhindra mikrobiell tillväxt och för ta bort bakterier från vatten. Två typer av antimikrobiella system har använts varefter den antimikrobiella effekten mot både mögel och bakterier utvärderats, med hjälp av både modellorganismer och mikrobiella odlingar från naturen.

Den första typen av antimikrobiell metod som använts baseras på en kontakt-aktivt teknik. Cellulosafibrer har modifierats genom lager-på-lager polyelektrolytadsorption för att skapa en positiv ytladdning som kan attrahera och binda bakterier till fiberytan. Studien visar att modifierade pappersfilter, med porer som är mycket större än bakterier, kan filtrera bort mer än 99,9 % av E. coli från kontaminerat vatten. De polyelektrolyt-modifierade cellulosamaterialen påvisade goda antibakteriella egenskaper men förhindrade inte tillväxt av mögel.

Den andra metoden som undersökts var att tillsätta biobaserade ämnen med antimikrobiella egenskaper till cellulosabaserade fiberskum. Kitosan och extraktivämnen från björkbark valdes ut som miljövänliga alternativ till vanliga biocider. Två typer av cellulosabaserade fiberskum har tagits fram och utvärderats för deras antimikrobiella egenskaper.

Avhandlingen visar hur viktigt det är att veta hur materialet är tänkt att användas och vilken typ av mikroorganism som skall undvikas när man väljer antimikrobiell behandling av biobaserade material. God förståelse för både materialvetenskap och mikrobiologi är nödvändig när nya biobaserade material med antimikrobiella egenskaper skall designas.

Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2018. p. 68
Series
TRITA-CBH-FOU ; 2018:57
Keywords
Antibacterial, antifungal, cellulosic, mold, bacteria, biobased, bio-based, renewable, insulation, packaging, water treatment, water purification, paper filter, paper, membrane, Antibakteriell, fungicid, mögel, antimögel, pappersfilter, vattenrening, membran, papper, bakterier, cellulosa, förpackning, isolering, förnyelsebar, biobaserade, nya material
National Category
Paper, Pulp and Fiber Technology Water Treatment Microbiology
Research subject
Fibre and Polymer Science
Identifiers
urn:nbn:se:kth:diva-238843 (URN)978-91-7873-031-5 (ISBN)
Public defence
2018-12-07, F3, Lindstedtsvägen 26, KTH Campus, Stockholm, 14:00 (English)
Opponent
Supervisors
Funder
ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 17-391Swedish Research Council Formas, 2014-00959
Note

QC 20181114

Available from: 2018-11-14 Created: 2018-11-12 Last updated: 2018-11-14Bibliographically approved

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  • ieee
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  • en-US
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  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
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Output format
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  • asciidoc
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