Effect of cellulose nanofibers from cassava pulp on physical properties of poly(lactic acid) biocomposites

2019 ◽  
Vol 33 (8) ◽  
pp. 1094-1108
Author(s):  
Thanh Chi Nguyen ◽  
Chaiwat Ruksakulpiwat ◽  
Yupaporn Ruksakulpiwat
Keyword(s):  
Lactic Acid ◽  
Cellulose Nanofibers ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Cassava Pulp ◽  
Lower Temperature ◽  
Alkali Hydrolysis ◽  
Internal Mixer

Biocomposites of poly(lactic acid) (PLA) and cellulose nanofibers (CNFs) extracted from cassava pulp were successfully prepared by melt mixing in an internal mixer. CNFs were prepared from cassava pulp by submitting to alkali hydrolysis, bleaching treatment, and acid hydrolysis. The compatibility between CNFs and PLA matrix was improved using glycidyl methacrylate (GMA) grafted PLA (PLA-g-GMA) as an effective compatibilizer. Higher elongation at break and impact strength of PLA/PLA-g-GMA/CNFs biocomposites was achieved compared to that of neat PLA. PLA-g-GMA shows a strong effect on the crystallization behavior of the biocomposites. The PLA/PLA-g-GMA/CNFs biocomposites induce cold crystallization to take place at lower temperature. Higher degree of crystallinity of PLA/PLA-g-GMA/CNFs biocomposites was obtained compared to PLA/CNFs biocomposites. The mechanical and thermal properties of PLA/CNFs biocomposites at various ratios were investigated. With increasing CNFs contents, the modulus of the biocomposites increases. Thermal stability of PLA/CNFs and PLA/PLA-g-GMA/CNFs biocomposites did not change significantly compared to that of neat PLA.

Biocomposites of Poly(Lactic Acid) and Cellulose Nanofibers from Cassava Pulp

2017 ◽  
Vol 753 ◽  
pp. 13-17
Author(s):  
Chi Nguyen Thanh ◽  
Ruksakulpiwat Chaiwat ◽  
Ruksakulpiwat Yupaporn
Keyword(s):  
Electron Microscopy ◽  
Lactic Acid ◽  
Impact Strength ◽  
Epoxy Group ◽  
Cellulose Nanofibers ◽  
Poly Lactic Acid ◽  
Melt Mixing ◽  
Hydrolysis Method ◽  
Cassava Pulp ◽  
The Impact

Cellulose nanofibers (CNFs) were used as biobased fillers to prepare poly(lactic acid) (PLA)-based biocomposites. Cellulose nanofibers were extracted from cassava pulp (CP) by acid hydrolysis method. Before submitted to acid treatment, CP was pre-treated by alkali and bleaching treatments. The biocomposites were prepared by melt mixing, followed by hot melt pressing. In order to improve the compatibility of CNFs with PLA matrix, glycidyl methacrylate (GMA) grafted poly (lactic acid) (PLA-g-GMA) was used as a compatibilizer. PLA-g-GMA was prepared by grafting of GMA onto PLA chain via melt mixing using an internal mixer. Transmission electron microscopy (TEM) micrograph shows that most nanofibers with the diameter in the range of 10-30 nm and immeasurable length were obtained. The appearance of two new peaks at 49.07 and 44.71 ppm in the carbon-13 nuclear magnetic resonance (13C-NMR) spectrum of PLA-g-GMA, which represent the carbons of the epoxy group of GMA, confirms that GMA was successfully grafted onto PLA chain. The morphology of biocomposites, characterized by scanning electron microscopy (SEM), reveals that without using PLA-g-GMA, the poor dispersion of CNFs in PLA matrix was observed. In contrast to that, with using PLA-g-GMA, the dispersion of CNFs in PLA matrix was improved. Moreover, the impact strength results show that by incorporating 1.0 wt% CNFs into PLA matrix and using PLA-g-GMA as a compatibilizer, the impact strength of biocomposites was slightly enhanced compared to that of pure PLA.

Improvement of Poly(Lactic Acid) Properties by Ethylene-Octene Copolymer and Organoclay

2020 ◽  
Vol 1009 ◽  
pp. 43-48
Author(s):  
Sirirat Wacharawichanant ◽  
Paweena Hanjai ◽  
Sanya Khongaio ◽  
Manop Phankokkruad
Keyword(s):  
Lactic Acid ◽  
Domain Size ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Before And After ◽  
Ethylene Octene Copolymer ◽  
Surface Modified ◽  
Internal Mixer ◽  
The Impact

The work studied the morphological, mechanical and thermal properties of poly(lactic acid) (PLA)/ethylene-octene copolymer (EOC) blends before and after adding the montmorillonite clay surface modified with 25-30% of octadecylamine (clay-ODA). The PLA/EOC blends and composites were prepared by melt mixing in an internal mixer. The EOC contents were 5, 10, 20, 30 wt% and clay-ODA contents were 1 and 3 phr. The morphology analysis showed that the addition of clay-ODA could improve the miscibility of PLA and EOC phases due to the domain size of dispersed EOC phase decreased with increasing clay-ODA content. X-ray diffraction revealed the formation of intercalated/exfoliated structure in PLA/clay-ODA and PLA blend composites. The mechanical properties showed that the impact strength of PLA/EOC blends dramatically increased with increasing EOC content up to 10 wt%. The strain at break of PLA blends increased with increasing EOC content. Moreover, the incorporation of clay-ODA increased significantly Young’s modulus of PLA and PLA/EOC blends with increasing clay-ODA content. The thermal stability of PLA/EOC blends improved with the addition of a small amount of clay-ODA.

scholarly journals Effects of Rutile–TiO2 Nanoparticles on Accelerated Weathering Degradation of Poly(Lactic Acid)

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1096 ◽  
Author(s):  
Ana Antunes ◽  
Anton Popelka ◽  
Omar Aljarod ◽  
Mohammad K. Hassan ◽  
Adriaan S. Luyt
Keyword(s):  
Molecular Weight ◽  
Lactic Acid ◽  
Exposure Time ◽  
Ageing Time ◽  
Modulation Frequency ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Accelerated Weathering ◽  
Mechanical And Thermal Properties ◽  
Rutile Tio2

The effect of accelerated weathering on poly(lactic acid) (PLA) and a PLA nanocomposite with rutile titanium (IV) dioxide (rutile–TiO2) was investigated. The accelerated weathering test applied consecutive steps of ultraviolet (UV) (at 340 nm and 0.76 W m−2 irradiance) and moisture at 50 °C for 2000 h, following the ASTM D4329 standard. The morphology, chemical structure, molecular weight, crystallization, as well as mechanical and thermal properties were thoroughly studied. Samples were characterized after 500 h, 1000 h and 2000 h exposure. Different degradation mechanisms were proposed to happen during the weathering exposure and confirmed based on the experimental data. The PLA and PLA/TiO2 surfaces presented holes and increasing roughness over the exposure time. The molecular weight of the weathered samples decreased due to chain scission during the degradation processes. Thermal stability decreased in the presence of TiO2 and a double melting peak was observed for the PLA/TiO2 nanocomposite. A general improvement in the mechanical properties of the PLA/TiO2 nanocomposite was observed over time during the accelerated weathering analysis up to 1000 h of exposure time. After 2000 h of weathering exposure, the PLA and PLA/TiO2 became extremely brittle and lost their ductile properties. This was ascribed to a significant increase in the degree of crystallinity upon weathering, which was accelerated in the presence of TiO2. Atomic force microscopy (AFM) using amplitude modulation–frequency modulation (AM–FM) tool confirmed the mechanical changes in the surface area of the PLA samples after accelerated weathering exposure. The stiffness and Young’s modulus achieved higher values than the unweathered ones up to 1000 h of exposure time. The changes in the physical and chemical properties of PLA/TiO2 over the ageing time confirm the photocatalytic activity of rutile–TiO2.

scholarly journals Bamboo Fiber Based Cellulose Nanocrystals/Poly(Lactic Acid)/Poly(Butylene Succinate) Nanocomposites: Morphological, Mechanical and Thermal Properties

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1076
Author(s):  
Masrat Rasheed ◽  
Mohammad Jawaid ◽  
Bisma Parveez
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Cellulose Nanocrystals ◽  
Natural Fiber ◽  
Testing Machine ◽  
Bamboo Fiber ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Butylene Succinate

The purpose of this work was to investigate the effect of cellulose nanocrystals (CNC) from bamboo fiber on the properties of poly (lactic acid) (PLA)/poly (butylene succinate) (PBS) composites fabricated by melt mixing at 175 °C and then hot pressing at 180 °C. PBS and CNC (0.5, 0.75, 1, 1.5 wt.%) were added to improvise the properties of PLA. The morphological, physiochemical and crystallinity properties of nanocomposites were analysed by field emission scanning electron microscope (FESEM), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD), respectively. The thermal and tensile properties were analysed by thermogravimetic analysis (TGA), Differential scanning calorimetry (DSC) and Universal testing machine (UTM). PLA-PBS blend shows homogeneous morphology while the composite shows rod-like CNC particles, which are embedded in the polymer matrix. The uniform distribution of CNC particles in the nanocomposites improves their thermal stability, tensile strength and tensile modulus up to 1 wt.%; however, their elongation at break decreases. Thus, CNC addition in PLA-PBS matrix improves structural and thermal properties of the composite. The composite, thus developed, using CNC (a natural fiber) and PLA-PBS (biodegradable polymers) could be of immense importance as they could allow complete degradation in soil, making it a potential alternative material to existing packaging materials in the market that could be environment friendly.

Comparison of Morphology and Mechanical Properties of Polyoxymethylene/Cellulose and Poly(Lactic Acid)/Cellulose Composites

2018 ◽  
Vol 916 ◽  
pp. 19-23 ◽  
Author(s):  
Sirirat Wacharawichanant ◽  
Nisarat Wimonsupakit ◽  
Sasithorn Kuhaudomlap
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Poly Lactic Acid ◽  
Melt Mixing ◽  
Cellulose Composites ◽  
Internal Mixer ◽  
The Impact ◽  
Morphology And Mechanical Properties

The objective of this study is to fabricate the polyoxymethylene (POM)/microcrystalline cellulose (MCC) and poly(lactic acid) (PLA)/MCC composites, and to compare the effect of MCC on the morphology and mechanical properties of POM and PLA. The polymer composites were prepared by melt mixing in an internal mixer and molded by compression molding. The MCC concentrations were 1, 3, 5, 7, 10, 15 and 10% by weight. From scanning electron microscopy study observes the fracture surface of POM and PLA composites is much rough and the roughness increases with increasing MCC content. This observation indicates MCC induces the ductile fracture characteristic of POM and PLA. The addition of MCC can improve the impact strength of PLA composite and improve Young’s modulus of both POM and PLA composites. While the tensile strength and strain at break decrease after adding MCC. In summary, MCC can enhance the morphology and mechanical properties of PLA composites is better than POM composites.

Effect of N,N′-ethylenebis(stearamide) on the water absorption and hydrolytic degradation of poly(lactic acid)/halloysite nanocomposites

2016 ◽  
Vol 30 (3) ◽  
pp. 416-433 ◽  
Author(s):  
WL Tham ◽  
BT Poh ◽  
ZA Mohd Ishak ◽  
WS Chow
Keyword(s):  
Lactic Acid ◽  
Water Absorption ◽  
Hydrolytic Degradation ◽  
Fickian Diffusion ◽  
Poly Lactic Acid ◽  
Melt Mixing ◽  
Hydrolysis Process ◽  
Different Temperatures ◽  
Lower Temperature ◽  
Kinetics Of

Poly(lactic acid)/halloysite nanoclay (PLA/HNC) nanocomposites with N, N′-ethylenebis(stearamide) (EBS) were produced by melt mixing. Water absorption behaviors of the PLA nanocomposites were studied at three different temperatures, that is, 30, 40, and 50°C. The water absorption kinetics of PLA/HNC nanocomposites conform to Fickian diffusion behavior at immersion temperatures of 30 and 40°C due to the diffusional exponent ( n) values that were close to 0.5 for all specimens. However, the hydrolysis of PLA occurred for longer time deviations at 50°C. Activation energy of water diffusion ( Ea) for PLA nanocomposites were found to be affected by the HNC and EBS contents. The glass transition temperature ( Tg), cold crystallization temperature ( Tcc), and melting temperature ( Tm) of the PLA sample were shifted to lower temperature after subjected to immersion temperature of 50°C. The carbonyl index of all PLA specimens increased after water absorption at 40 and 50°C due to the formation of higher amount of carboxylic acid end groups during the hydrolysis process.

scholarly journals Effect of HNT on mechanical and thermal properties of poly(lactic acid)/polypropylene carbonate blends

Polimery ◽  
2021 ◽  
Vol 66 (9) ◽  
pp. 459-465
Author(s):  
Intan Najwa Humaira Mohamed Haneef ◽  
Yose Fachmi Buys ◽  
Norhashimah Mohd Shaffiar ◽  
Sharifah Imihezri Syed Shaharuddin ◽  
Abdul Malek Abdul Hamid ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Thermal Properties ◽  
Halloysite Nanotubes ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Elongation At Break ◽  
Young’S Moduli ◽  
Dsc Thermograms

In this work, the influence of halloysite nanotubes (HNTs) on the mechanical and thermal properties of the poly(lactic acid)/polypropylene carbonate (PLA/PPC 70/30) blend was studied. The HNT was incorporated into the PLA/PPC blend by melt mixing. It was found that addition of 2-6 wt % HNT successfully improved the tensile and flexural strength as well as the flexural and Young’s  moduli of PLA/PPC blend, due to the reinforcing effect. Although the elongation at break decreases with increasing HNT content, its value is much higher than that of pure PLA. Moreover, the addition of HNT didnot affect the miscibility of PLA and PPC, since two glass transition temperatures were observed in the DSC thermograms. However, a higher content of HNT may improve the compatibility between PLA and PPC as evidenced by the lower difference between the glass transition temperature of PPC and PLA and reduced crystallinity resulting in higher tensile strength of nanocomposites.Keywords: PLA, PPC, HNT, mechanical properties, thermal properties.

Morphology and Properties of Poly(Lactic Acid)/Ethylene-Octene Copolymer Nanocomposites

2019 ◽  
Vol 953 ◽  
pp. 47-52
Author(s):  
Sirirat Wacharawichanant ◽  
Attachai Sriwattana ◽  
Kulaya Yaisoon ◽  
Manop Phankokkruad
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Lactic Acid ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Melt Mixing ◽  
Ethylene Octene Copolymer ◽  
Thermal Stability Of

The effects of the montmorillonite clay surface modified with 0.5-5 wt% aminopropyltriethoxysilane and 15-35% octadecylamine (Clay-APTSO) on morphology, mechanical and thermal properties of poly(lactic acid) (PLA)/ethylene-octene copolymer (EOC)/Clay-APTSO composites were investigated. The blends of PLA/EOC with and without Clay-APTSO were prepared by melt mixing in an internal mixer. Scanning electron microscopy analysis observed the morphology of PLA/EOC blends demonstrated a phase separation of minor phase and matrix phase. The addition of Clay-APTSO in PLA/EOC blends showed significant decreased in droplet size of dispersed EOC phase, thus, Clay-APTSO acted as an effective compatibilizer in the PLA/EOC blends. The results of tensile properties found the decrease of Young’s modulus of PLA when added EOC due to the low modulus and flexibility of EOC. While the incorporation of Clay-APTSO increased significantly Young’s modulus of PLA/EOC blends at low EOC and Clay-APTSO content. The strain at break of the blends increased with the increase of EOC loading, this indicated the presence of EOC enhanced the elongation at break of PLA, while the addition Clay-APTSO reduced the strain at break of PLA/EOC blends. The tensile strength of all blend compositions improved when added Clay-APTSO and the tensile strength showed the highest value at 3 phr of Clay-APTSO. The thermal stability of PLA/EOC blends did not change when compared with neat PLA, and when added Clay-APTSO in the blends could improve the thermal stability of the PLA/EOC blends.

scholarly journals Influence of time and room temperature on mechanical and thermal degradation of poly(lactic) acid

2019 ◽  
Vol 23 (Suppl. 1) ◽  
pp. 383-390 ◽  
Author(s):  
Mehlika Karamanlioglu ◽  
Umit Alkan
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Incubation Time ◽  
Room Temperature ◽  
Incubation Temperature ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Main Concern ◽  
Mechanical And Thermal Properties ◽  
Low Humidity

Poly(lactic) acid (PLA), is a compostable thermoplastic which degrades fast under composting conditions of microorganisms, high humidity, and temperatures. However, PLA degrades slowly below its glass transition temperature and in low humidity, hence, when used as short-shelf life product containers and not disposed to composting systems, PLA may cause environmental pollution. Therefore, when not disposed to proper waste management systems, the effect of long incubation time at room temperature on mechanical and thermal properties of PLA is the main concern of this study. To determine the effect of room temperature on semi-crystalline PLA degradation at a low humidity percentage, PLA films (PLA2) were kept at room temperature for 5 years at 40?10% humidity. Some PLA films (PLA3) were pre-treated at 55?C under dry conditions for one year and then kept at room temperature for four years. Influence of incubation time and temperature on PLA degradation was evaluated by mechanical, thermal analyses and by FTIR spectroscopy analysis and compared with the initial PLA samples (PLA1). Mainly mechanical properties of PLA were affected by incubation temperature and time since 68% tensile strength loss was observed in PLA3 samples which were pre-treated at 55?C and 34% decrease in tensile strength was observed in PLA2 samples. Ther?mal behavior of PLA was also influenced by incubation time and temperature as degree of crystallinity decreased 5% and 3% in PLA2 and PLA3 samples, respectively. Deformation of CH bonds and amorphous phase degradation were revealed by FTIR analyses in PLA2 and PLA3 samples.

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