Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The development of a new wood adhesive for load bearing wood constructions: A study of the mechanical properties and characteristics
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
2018 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Utveckling av en ny generation trälim (Swedish)
Abstract [en]

The harsh demands on emissions of toxic formaldehyde and isocyanate has left the industry seek for adhesive with low or no emission of these substances, particularly for XXX XXX XXX XXX. In this report, two new formaldehyde and isocyanate free adhesive systems has been evaluated. These systems contain a XXX backbone that is XXX with XXX, thereby forming XXX. The XXX react through XXX to form XXX XXX that XXX forms XXX by XXX. The mechanical properties were examined through industry standardized bonding tests, and comparisons were made with commercially used XXX systems. To obtain a better understanding of the properties of the adhesive system, the curing time and reaction mechanism was studied by rheometer and infrared spectroscopy (FTIR) respectively. Additionally, the penetration characteristics of the glue-line were examined through Scanning electron microscopy (SEM). The incorporation of XXX and XXX XXX was also examined to test whether one could increase the glue joint strength.The main difficulty with the XXX used was that they, almost in all tests, had shear strengths in dry conditions that has met with the required values from the industry standards (XXX) However, in wet conditions the adhesive had values XXX below the requirements (XXX). An adhesive system with XXX added as XXX showed the highest shear strength in wet conditions showing that the incorporation of:XXX can help with the shear strength of the adhesive system, but this value is still XXX below the required value. The addition of XXX as XXX to the adhesive system didn't show any significant improvements in the overall shear strength for the systems. When performing tensile tests of pure adhesive films, the strength in wet conditions exceeded required values, showing that the intrinsic properties of the adhesive are not the main problem but rather it is the combination of a XXX glue line ( as observed with SEM) with the XXX between XXX and the XXX. The SEM study did show that the penetration decreased slightly with the incorporation of:XXX, suggesting that XXX may be one of the reasons for the XXX water resistances when not formulated By evaluation of the curing process of:XXX and XXX with XX and XX as XXX XXX, it was seen that it was possible to control the curing process depending on concentration and XXX of the XXX XXX to some extent. Lower concentrations of XXX XXX with long curing times were difficult to control since small deviations in amounts seem to affect the curing to a large extent and the overall curing times were thereby difficult to replicate. The FTIR study of the curing process didn't show any differences in the curing process between XXX and XXX. With FTIR, the XXX could be monitored by evaluating XXX XXX present in the adhesive and the XXX XXX in the process. The XXX of XXX could not be detected using FTIR due to obstruction by other XXX in the same XXX, but it was apparent that XXX XXX XXX after approximately half the reaction time (as determined by rheometer) most likely followed by XXX.

Abstract [sv]

Tuffare krav gallande farliga emissioner av formaldehyd och isocyanat har gjort att industrin nu soker efter lim utan dessa farliga kemikalier. I denna rapport undersoks tva nya formaldehyd-och isocyanat fria limsystem for XXX XXX. Dessa system ar XXX. Dessa system kallas for XXX . XXX reagerar genom XXX, dar XXX XXX. XXX reagerar darefter genom XXX och XXX XXX, som ar XXX for systemet. Skjuvstyrkan av limmade traamnen utvarderades genom industristandarder och jamforelser gjordes med kommersiellt tillgangliga XXX. For en okad forstaelse av limmets egenskaper, anvandes reometer for att utvardera hardningstider och genom infrarod spektroskopi (FTIR) kunde limmets hardningsforlopp foljas. Limmets penetration studerades med svepelektronmikroskap (SEM) for att forsta hur penetration och fogtjocklek kan forandra limningsegenskapema.X:XX och XXX XXX utvarderades aven for att se hur dessa paverkar skjuvstyrkan for de limmade traamnena.Den storsta svarigheten med XXX som anvandes var deras daliga vattenresistans. Detta tros vara till foljd av en XXX limfog och darfor testades formuleringar for att oka viskositeten for att oka mangden lim i fogen. Genom att formulera limmet med XXX kunde skjuvstyrkan i vata forhallanden oka markant och prover i SEM visade aven att dessa system hade den tjockaste limfogen. Skjuvstyrkan med XXX ar dock fortfarande under godkanda varden enligt standarden sa andra egenskaper an utarmad limfog verkar paverka limningsegenskapema. Nar XXX anvandes som XXX sags inga markanta forbattringar for skjuvstyrkan for alla system som testades och SEM visade ett fortunnande av limfogen med XXX. For att testa limmets egenskaper drogs tunna limfilmer som dragprovades. Dessa limfilmer hade dragstyrkor hogre an godkannande varden for industristandarden i bade torra och vata betingelser, vilket visar att de inneboende egenskapema hos limmet formodligen inte ar problemet utan det ar snarare en kombination av en utarmad fog (aven sett i SEM) samt XXX mellan XXX och XXX som ger upphov till den daliga vattenresistansen i limningama. Genom utvardering av hardningsforloppet av XXX och XXX med XXX och XXX som hardare med reometer, kunde man se att hardningsforloppet kan styras till en viss grad beroende av koncentrationen av hardaren. Langre hardningsforlopp som hade laga koncentrationer av hardare var svarare att styra da sma variationer i mangder paverkade hardningstiden mycket. Detta gjorde att det var svart att gora repetitioner av forsoken och sakerstalla hardningstidema. FTIR visade inga skillnader i hardningsforlopp mellan XXX och XXX som hardare. Med FTIR kunde hardningsforloppet foljas genom att folja minskningen av XXX och okningen av XXX. Nar halften av hardningen var fullfoljd minskade XXX av XXX och reaktionen verkade avstanna vilket indikerar pa XXX av XXX. XXX kunde dock inte foljas pa grund av XXX av andra toppar som lag inom XXX XXX.

Place, publisher, year, edition, pages
2018.
National Category
Chemical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-231561OAI: oai:DiVA.org:kth-231561DiVA, id: diva2:1229234
Available from: 2018-06-29 Created: 2018-06-29 Last updated: 2018-06-29Bibliographically approved

Open Access in DiVA

No full text in DiVA

By organisation
School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH)
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf