materials-congress-2018-posters-abstracts

11 / 41

Materials Congress 2018
Page 57
Nano Research & Applications
ISSN: 2471-9838
W o r l d C o n g r e s s o n
Materials Science & Engineering
A u g u s t 2 3 - 2 5 , 2 0 1 8
Am s t e r d a m , N e t h e r l a n d s
Polylactide (PLA) is biodegradable thermoplastic polyester with potential
to replace conventional petrochemical-based polymers. Plasticized PLA is
often found in many uses to avoid brittle fracture. In this work, cashew nut shell
liquid (CNSL), a natural oil mainly consisting of cardanol (a phenolic lipid), was
used as a plasticizer. In order to avoid its bleeding from the PLA bulk, it was
added as an initiator during bulk ring-opening polymerization of lactide such
that it was immobilized onto the PLA chains. The immobilized CNSL-plasticized
PLA obtained from the synthesis has rather low molecular weight. Adding
this natural oil at fixed content of 3% wt can reduce molecular weight of PLA.
From Gel Permeation Chromatography (GPC) results, molecular weight of the
(3% wt) immobilized CNSL-plasticized PLA were 3.93x10 -4 g/mol, compared
to 4.32x10-4 g/mol of the synthesized PLA. A chain extender, hexamethylene
diisocyanate (HDI), is then added and varied from 1, 3, 5, 7% wt to further
enhance the molecular weight of the (3% wt) immobilized CNSL-plasticized
PLA. The maximum molecular weight of 5.03x10-4 g/mol is obtained by adding
5% wt HDI. From melt flow indexer (MFI) results, this immobilized CNSL-
plasticized PLA has the lowest melt flow index value of 51.4g/10 mins which
means that it has the highest molecular weight. Also, the immobilized CNSL-
plasticized PLA with various HDI contents were subsequently investigated for
their chemical structures by Fourier-transform Infrared Spectroscopy (FT-IR)
and found that the characteristic ester absorption band appeared at 1691
cm-1 according to -C=O adjoining to -NH. From nuclear magnetic resonance
(NMR) results, the chemical shifts at 3.2 ppm and 4.1 ppm were observed
and assigned to the unit of HDI in PLA chains. Moreover, differential scanning
calorimetry (DSC) results showed that increasing HDI content made Tg and Tm
move toward lower temperature as a result of long chain alkane unit of HDI.
Biography
Supanut Kitphaitun has completed Bachelor’s degree from
King Mongkut’s Institute of Technology Ladkrabang, a major
in Nanomaterials Engineering with 1st honours. Now, he is
pursuing Master’s degree of Polymer Science at the Petroleum
and Petrochemical College, Chulalongkorn University. He is a
working under supervision of Prof. Rathanawan Magaraphan.
Improving molecular weight of natural oil-plasticized PLA by
chain extender
Supanut Kitphaitun and M Rathanawan
The Petroleum and Petrochemical College, Thailand
Supanut Kitphaitun et al., Nano Res Appl 2018, Volume: 4
DOI: 10.21767/2471-9838-C4-018