Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites
Dalam penyelidikan ini, nanotiub haloisit (HNT) telah digunakan untuk meningkatkan sifat-sifat poli(asid laktik) (PLA). Nanokomposit PLA/HNT telah disediakan dengan kaedah penyebatian leburan diikuti oleh pengacuan mampatan. Tiga jenis pengubahsuai hentaman, iaitu kopolimer stirena-etilena/butile...
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T Technology TN263-271 Mineral deposits. Metallic ore deposits. Prospecting |
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T Technology TN263-271 Mineral deposits. Metallic ore deposits. Prospecting Tham, Wei Ling Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites |
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Dalam penyelidikan ini, nanotiub haloisit (HNT) telah digunakan untuk
meningkatkan sifat-sifat poli(asid laktik) (PLA). Nanokomposit PLA/HNT telah
disediakan dengan kaedah penyebatian leburan diikuti oleh pengacuan mampatan.
Tiga jenis pengubahsuai hentaman, iaitu kopolimer stirena-etilena/butilena-stirena
tercantum maleik anhidrida (SEBS-g-MA), N,N’-etilenabis(stearamida) (EBS), dan
getah asli terepoksida (ENR) telah digunakan untuk memperliat nanokomposit PLA.
Sifat-sifat nanokomposit PLA/HNT telah dicirikan oleh ujian mekanik (ujian
tegangan, lenturan, hentaman), analisis termal (kalorimetri pengimbasan pembezaan
(DSC) dan analisis termogravimetri (TGA)), analisis morfologi (iaitu ujian
mikroskopi elektron imbasan pancaran medan (FESEM) dan mikroskopi elektron
pemancaran (TEM)), dan spektroskopi inframerah jelmaan Fourier (FTIR). Kekuatan
hentaman bagi nanokomposit PLA/HNT telah meningkat sebanyak 300% dengan
penambahan 15 wt% ENR. Dengan penambahan EBS dan ENR, HNT yang terserak
halus dapat meningkatkan kesan penukleusan dan membantu dalam proses
penghabluran bagi PLA. Walau bagaimanapun, penambahan SEBS-g-MA dan HNT
melambatkan pembentukan kumin hablur yang bersaiz besar di dalam PLA. Kinetik
penyerapan air bagi nanokomposit PLA/HNT adalah mengikut kelakuan hukum
resapan Fickian pada suhu rendaman 30oC dan 40oC. Bagi sampel terdedah kepada
50oC, penyerapan air mematuhi hukum Fick di peringkat awal. Namun, semakin
lama direndam, sampel tersebut didapati tidak lagi mematuhi hukum Fick dan
kehilangan berat berlaku. Hal ini disebabkan oleh hidrolisis PLA pada suhu
rendaman yang tinggi yang telah disahkan melalui perubahan pH, pengurangan berat
molekul, peningkatan nilai-nilai indeks karbonil (CI), dan perubahan sifat termal.
Daripada keputusan TGA, didapati bahawa penguraian tunggal berlaku ketika
keadaan nitrogen, manakala proses penguraian dua-peringkat telah berlaku dalam
keadaan oksigen. Penambahan EBS dan ENR dapat meningkatkan kestabilan termal
bagi PLA/HNT di bawah keadaan oksigen. Nanokomposit PLA/HNT6/ENR5
mempunyai kestabilan termo-beroksida yang tinggi di bawah atmosfera oksigen.
Selain itu, penambahan 5 wt% ENR dalam nanokomposit PLA/HNT6 menganjakkan
suhu permulaan pengoksidaan (OOT) kepada suhu yang lebih tinggi (dari 239.5oC
kepada 296.5oC). Nanokomposit PLA/HNT6/ENR5 telah menunjukkan nilai pekali
kebolehtelapan oksigen ( O2 P ) yang terendah (1.567x10-4 cm3.m.m-2.day-1.kPa-1).
Walau bagaimanapun, penambahan SEBS-g-MA tidak dapat meningkatkan sifatsifat
halangan gas oksigen bagi nanokomposit PLA/HNT. Daripada analisis
spektroskopi UV-Vis, penambahan pengubahsuai hentaman di dalam nanokomposit
PLA/HNT telah mengurangkan penembusan cahaya dan hampir tiada cahaya UV
dihantar melalui filem pada 300 nm. Namun, kesemua nanokomposit PLA/HNT
kekal lutsinar melalui pengamatan visual. Kesimpulannya, penambahan ENR dalam
nanokomposit PLA/HNT dapat meningkatkan sifat-sifat nanokomposit polimer
secara efektif dari segi kekuatan hentaman, tenaga pengaktifan resapan air (Ea), OOT,
dan ciri-ciri halangan gas oksigen.
________________________________________________________________________________________________________________________
In this research, halloysite nanotube (HNT) was used to improve the properties of
poly(lactic acid) (PLA). The PLA/HNT nanocomposites were prepared using melt
compounding followed by compression molding. Three types of impact modifiers
i.e., maleic anhydride grafted styrene-ethylene/butylene-styrene copolymer (SEBS-g-
MA), N,N’-ethylenebis(stearamide) (EBS), and epoxidized natural rubber (ENR),
were used to toughen the PLA nanocomposites. The properties of PLA/HNT
nanocomposites were characterized by mechanical tests (i.e., tensile, flexural, and
impact tests), thermal analysis (i.e., differential scanning calorimetry (DSC) and
thermogravimetric analysis (TGA)), morphological analysis (i.e., field emission
scanning electron microscopy (FESEM) and transmission electron microscopy
(TEM)), and Fourier transform infrared spectroscopy (FTIR). The impact strength of
PLA/HNT nanocomposites was increased significantly to approximately 300% by
the addition of 15 wt% ENR. A finely dispersed HNT could eventually increase its
nucleation effect and assist in the crystallization process of PLA whilst in the
presence of EBS and ENR. Nevertheless, the presence of SEBS-g-MA and HNT
retard the formation of large crystallites of PLA. The kinetics of water absorption of
PLA/HNT nanocomposite fitted Fickian diffusion behaviour at immersion
temperatures of 30oC and 40oC. For the samples exposed to 50oC, the water uptake
followed Fick's law during the initial stages, but at longer time periods, deviations
and weight loss were observed. This may have been due to the hydrolysis of PLA at
higher immersion temperatures, which was confirmed by the pH change, reduction of
molecular weight, increase in carbonyl index (CI) values, and thermal property
changes. From the TGA results, it was found that single decomposition took place in
the nitrogen atmosphere, while a double-stage decomposition process occurred in the
oxygen atmosphere. The incorporation of EBS and ENR could improve the thermal
stability of PLA/HNT under oxygen atmosphere. The PLA/HNT6/ENR5
nanocomposites exhibited high thermo-oxidative stability under oxygen atmosphere.
Furthermore, the addition of 5 wt% of ENR in PLA/HNT6 nanocomposites increased
the oxidation onset temperature (OOT) (from 239.5oC to 296.5oC). The
PLA/HNT6/ENR5 showed the lowest oxygen permeability coefficient ( O2 P ) value of
approximately 1.567x10-4 cm3.m.m-2.day-1.kPa-1. However, the incorporation of
SEBS-g-MA could not improve the oxygen gas barrier properties of PLA/HNT
nanocomposites. From the UV-Vis spectroscopy analysis, the incorporation of
impact modifiers in PLA/HNT nanocomposites decreases light transmittance and
nearly no UV light can be transmitted through thin film at 300 nm. Nevertheless, all
PLA/HNT nanocomposites remain transparent from visual view. In summary, the
addition of ENR in PLA/HNT nanocomposites can effectively improve the
properties of polymer nanocomposites in term of impact strength, activation energy
of water diffusion (Ea), OOT, and oxygen gas barrier properties among the others
impact modifiers.
|
| format |
Thesis |
| author |
Tham, Wei Ling |
| author_facet |
Tham, Wei Ling |
| author_sort |
Tham, Wei Ling |
| title |
Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites |
| title_short |
Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites |
| title_full |
Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites |
| title_fullStr |
Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites |
| title_full_unstemmed |
Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites |
| title_sort |
preparation and properties of poly (lactic acid) halloysite nanotube nanocomposites |
| publishDate |
2015 |
| url |
http://eprints.usm.my/41014/1/Preparation_and_properties_of_poly_%28lactic_acid%29_halloysite_nanotube_nanocomposites.pdf http://eprints.usm.my/41014/ |
| _version_ |
1643710103900127232 |
| spelling |
my.usm.eprints.41014 http://eprints.usm.my/41014/ Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites Tham, Wei Ling T Technology TN263-271 Mineral deposits. Metallic ore deposits. Prospecting Dalam penyelidikan ini, nanotiub haloisit (HNT) telah digunakan untuk meningkatkan sifat-sifat poli(asid laktik) (PLA). Nanokomposit PLA/HNT telah disediakan dengan kaedah penyebatian leburan diikuti oleh pengacuan mampatan. Tiga jenis pengubahsuai hentaman, iaitu kopolimer stirena-etilena/butilena-stirena tercantum maleik anhidrida (SEBS-g-MA), N,N’-etilenabis(stearamida) (EBS), dan getah asli terepoksida (ENR) telah digunakan untuk memperliat nanokomposit PLA. Sifat-sifat nanokomposit PLA/HNT telah dicirikan oleh ujian mekanik (ujian tegangan, lenturan, hentaman), analisis termal (kalorimetri pengimbasan pembezaan (DSC) dan analisis termogravimetri (TGA)), analisis morfologi (iaitu ujian mikroskopi elektron imbasan pancaran medan (FESEM) dan mikroskopi elektron pemancaran (TEM)), dan spektroskopi inframerah jelmaan Fourier (FTIR). Kekuatan hentaman bagi nanokomposit PLA/HNT telah meningkat sebanyak 300% dengan penambahan 15 wt% ENR. Dengan penambahan EBS dan ENR, HNT yang terserak halus dapat meningkatkan kesan penukleusan dan membantu dalam proses penghabluran bagi PLA. Walau bagaimanapun, penambahan SEBS-g-MA dan HNT melambatkan pembentukan kumin hablur yang bersaiz besar di dalam PLA. Kinetik penyerapan air bagi nanokomposit PLA/HNT adalah mengikut kelakuan hukum resapan Fickian pada suhu rendaman 30oC dan 40oC. Bagi sampel terdedah kepada 50oC, penyerapan air mematuhi hukum Fick di peringkat awal. Namun, semakin lama direndam, sampel tersebut didapati tidak lagi mematuhi hukum Fick dan kehilangan berat berlaku. Hal ini disebabkan oleh hidrolisis PLA pada suhu rendaman yang tinggi yang telah disahkan melalui perubahan pH, pengurangan berat molekul, peningkatan nilai-nilai indeks karbonil (CI), dan perubahan sifat termal. Daripada keputusan TGA, didapati bahawa penguraian tunggal berlaku ketika keadaan nitrogen, manakala proses penguraian dua-peringkat telah berlaku dalam keadaan oksigen. Penambahan EBS dan ENR dapat meningkatkan kestabilan termal bagi PLA/HNT di bawah keadaan oksigen. Nanokomposit PLA/HNT6/ENR5 mempunyai kestabilan termo-beroksida yang tinggi di bawah atmosfera oksigen. Selain itu, penambahan 5 wt% ENR dalam nanokomposit PLA/HNT6 menganjakkan suhu permulaan pengoksidaan (OOT) kepada suhu yang lebih tinggi (dari 239.5oC kepada 296.5oC). Nanokomposit PLA/HNT6/ENR5 telah menunjukkan nilai pekali kebolehtelapan oksigen ( O2 P ) yang terendah (1.567x10-4 cm3.m.m-2.day-1.kPa-1). Walau bagaimanapun, penambahan SEBS-g-MA tidak dapat meningkatkan sifatsifat halangan gas oksigen bagi nanokomposit PLA/HNT. Daripada analisis spektroskopi UV-Vis, penambahan pengubahsuai hentaman di dalam nanokomposit PLA/HNT telah mengurangkan penembusan cahaya dan hampir tiada cahaya UV dihantar melalui filem pada 300 nm. Namun, kesemua nanokomposit PLA/HNT kekal lutsinar melalui pengamatan visual. Kesimpulannya, penambahan ENR dalam nanokomposit PLA/HNT dapat meningkatkan sifat-sifat nanokomposit polimer secara efektif dari segi kekuatan hentaman, tenaga pengaktifan resapan air (Ea), OOT, dan ciri-ciri halangan gas oksigen. ________________________________________________________________________________________________________________________ In this research, halloysite nanotube (HNT) was used to improve the properties of poly(lactic acid) (PLA). The PLA/HNT nanocomposites were prepared using melt compounding followed by compression molding. Three types of impact modifiers i.e., maleic anhydride grafted styrene-ethylene/butylene-styrene copolymer (SEBS-g- MA), N,N’-ethylenebis(stearamide) (EBS), and epoxidized natural rubber (ENR), were used to toughen the PLA nanocomposites. The properties of PLA/HNT nanocomposites were characterized by mechanical tests (i.e., tensile, flexural, and impact tests), thermal analysis (i.e., differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)), morphological analysis (i.e., field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM)), and Fourier transform infrared spectroscopy (FTIR). The impact strength of PLA/HNT nanocomposites was increased significantly to approximately 300% by the addition of 15 wt% ENR. A finely dispersed HNT could eventually increase its nucleation effect and assist in the crystallization process of PLA whilst in the presence of EBS and ENR. Nevertheless, the presence of SEBS-g-MA and HNT retard the formation of large crystallites of PLA. The kinetics of water absorption of PLA/HNT nanocomposite fitted Fickian diffusion behaviour at immersion temperatures of 30oC and 40oC. For the samples exposed to 50oC, the water uptake followed Fick's law during the initial stages, but at longer time periods, deviations and weight loss were observed. This may have been due to the hydrolysis of PLA at higher immersion temperatures, which was confirmed by the pH change, reduction of molecular weight, increase in carbonyl index (CI) values, and thermal property changes. From the TGA results, it was found that single decomposition took place in the nitrogen atmosphere, while a double-stage decomposition process occurred in the oxygen atmosphere. The incorporation of EBS and ENR could improve the thermal stability of PLA/HNT under oxygen atmosphere. The PLA/HNT6/ENR5 nanocomposites exhibited high thermo-oxidative stability under oxygen atmosphere. Furthermore, the addition of 5 wt% of ENR in PLA/HNT6 nanocomposites increased the oxidation onset temperature (OOT) (from 239.5oC to 296.5oC). The PLA/HNT6/ENR5 showed the lowest oxygen permeability coefficient ( O2 P ) value of approximately 1.567x10-4 cm3.m.m-2.day-1.kPa-1. However, the incorporation of SEBS-g-MA could not improve the oxygen gas barrier properties of PLA/HNT nanocomposites. From the UV-Vis spectroscopy analysis, the incorporation of impact modifiers in PLA/HNT nanocomposites decreases light transmittance and nearly no UV light can be transmitted through thin film at 300 nm. Nevertheless, all PLA/HNT nanocomposites remain transparent from visual view. In summary, the addition of ENR in PLA/HNT nanocomposites can effectively improve the properties of polymer nanocomposites in term of impact strength, activation energy of water diffusion (Ea), OOT, and oxygen gas barrier properties among the others impact modifiers. 2015-09 Thesis NonPeerReviewed application/pdf en http://eprints.usm.my/41014/1/Preparation_and_properties_of_poly_%28lactic_acid%29_halloysite_nanotube_nanocomposites.pdf Tham, Wei Ling (2015) Preparation And Properties Of Poly (Lactic Acid) Halloysite Nanotube Nanocomposites. PhD thesis, Universiti Sains Malaysia. |
| score |
13.211869 |