scholarly journals Impact of the Graphite Fillers on the Thermal Processing of Graphite/Poly(lactic acid) Composites

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5346
Author(s):  
Daniel Kaczor ◽  
Kacper Fiedurek ◽  
Krzysztof Bajer ◽  
Aneta Raszkowska-Kaczor ◽  
Grzegorz Domek ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Polymer Matrix ◽  
Thermal Processing ◽  
Poly Lactic Acid ◽  
Expandable Graphite ◽  
Slight Reduction ◽  
Melt Mixing ◽  
Neat Polymer ◽  
Industrial Grade ◽  
The Impact

To assess the impact of graphite fillers on the thermal processing of graphite/poly(lactic acid) (PLA) composites, a series of the composite samples with different graphite of industrial grade as fillers was prepared by melt mixing. The average size of the graphite grains ranged between 100 µm and 6 µm. For comparative purposes, one of the carbon fillers was expandable graphite. Composites were examined by SEM, FTIR, and Raman spectroscopy. As revealed by thermogravimetric (TG) analyses, graphite filler slightly lowered the temperature of thermal decomposition of the PLA matrix. Differential scanning calorimetry (DSC) tests showed that the room temperature crystallinity of the polymer matrix is strongly affected by the graphite filler. The crystallinity of the composites determined from the second heating cycle reached values close to 50%, while these values are close to zero for the neat polymer. The addition of graphite to PLA caused a slight reduction in the oxidation induction time (OIT). The melt flow rate (MFR) of the graphite/PLA composites was lower than the original PLA due to an increase in flow resistance associated with the high crystallinity of the polymer matrix. Expandable graphite did not cause changes in the structure of the polymer matrix during thermal treatment. The crystallinity of the composite with this filler did not increase after first heating and was close to the neat PLA MFR value, which was extremely high due to the low crystallinity of the PLA matrix and delamination of the filler at elevated temperature.

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.

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.

Morphology, thermal and dynamic mechanical properties of poly(lactic acid)/expandable graphite (PLA/EG) flame retardant composites

2017 ◽  
Vol 32 (1) ◽  
pp. 89-107 ◽  
Author(s):  
Mfiso Emmanuel Mngomezulu ◽  
Adriaan Stephanus Luyt ◽  
Maya Jacob John
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Glass Transition ◽  
Flame Retardant ◽  
Dynamic Mechanical Properties ◽  
Poly Lactic Acid ◽  
Expandable Graphite ◽  
Damping Factor ◽  
Melt Mixing ◽  
Dynamic Mechanical

This work reports on the effect of expandable graphite (EG) on the morphology, thermal and dynamic mechanical properties of flame retardant poly(lactic acid) (PLA)/EG composites. The composites were prepared by melt-mixing and their structure, morphology, melting and crystallization behaviour, as well as their dynamic mechanical properties, were investigated. It was found that graphite layers still existed in an aggregate structure with poor filler dispersion resulting in a lack of interfacial adhesion between EG and the PLA matrix. The presence of EG did not favour the crystallization of PLA, increased the glass transition temperature and showed a reduction in the crystallinity of the composites. The composites with higher filler contents showed enhanced storage and loss moduli. The glass transition temperatures from the loss modulus and damping factor curves varied inconsistently with EG content. The use of commercial EG as filler in PLA can preserve the thermal properties of injection moulding grade Cereplast 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.

Preparation and characterization of EVA/PLA/sugarcane bagasse composites for water purification

2016 ◽  
Vol 51 (9) ◽  
pp. 1169-1186 ◽  
Author(s):  
TA Makhetha ◽  
K Mpitso ◽  
AS Luyt
Keyword(s):  
Lactic Acid ◽  
Vinyl Acetate ◽  
Sugarcane Bagasse ◽  
Ethylene Vinyl Acetate ◽  
Poly Lactic Acid ◽  
Melt Mixing ◽  
Lower Viscosity ◽  
Monolayer Adsorption ◽  
Sample Water ◽  
The Impact

Poly(lactic acid)/ethylene vinyl acetate blends and poly(lactic acid)/ethylene vinyl acetate/sugarcane bagasse composites were prepared by melt mixing. The lower viscosity of poly(lactic acid), the lower interfacial tension between poly(lactic acid) and sugarcane bagasse, and the wetting coefficient of poly(lactic acid)/sugarcane bagasse being larger than one, all suggested that sugarcane bagasse would preferably be in contact with poly(lactic acid). A fairly good dispersion of sugarcane bagasse was observed in the composites. Exposed fibre ends were observed in the composite micrographs, which were believed to add to the efficiency of metal adsorption. The impact properties depended more on the poly(lactic acid):ethylene vinyl acetate ratio than on the presence of sugarcane bagasse. The poly(lactic acid)/ethylene vinyl acetate blends showed two melting peaks at approximately the same temperatures as those of the neat polymers, which confirms the complete immiscibility of poly(lactic acid) and ethylene vinyl acetate at all the investigated compositions. Sugarcane bagasse-related weight loss occurred at higher temperatures for sugarcane bagasse in the composites, which could have been the result of the sugarcane bagasse being protected by the polymers, or a delay in the diffusion of the sugarcane bagasse decomposition products out of the sample. Water absorption increased with an increase in sugarcane bagasse loading in the composites. More lead was adsorbed than one would expect if the partial coverage of the fibre by the polymer is taken into account, and therefore it may be assumed that some of the lead was trapped inside the cavities in the composites and that the polymers may also have played a role in the metal complexation process, since both polymers have functional groups that could interact with the lead ions. The metal impurities underwent monolayer adsorption.

scholarly journals Poly(Lactic Acid)–Poly(Butylene Succinate)–Sugar Beet Pulp Composites; Part I: Mechanics of Composites with Fine and Coarse Sugar Beet Pulp Particles

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2531
Author(s):  
Rodion Kopitzky
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Sugar Beet ◽  
Cell Structure ◽  
Sugar Beet Pulp ◽  
Poly Lactic Acid ◽  
Butylene Succinate ◽  
Fracture Patterns ◽  
Beet Pulp ◽  
The Impact

Sugar beet pulp (SBP) is a residue available in large quantities from the sugar industry, and can serve as a cost-effective bio-based and biodegradable filler for fully bio-based compounds based on bio-based polyesters. The heterogeneous cell structure of sugar beet suggests that the processing of SBP can affect the properties of the composite. An “Ultra-Rotor” type air turbulence mill was used to produce SBP particles of different sizes. These particles were processed in a twin-screw extruder with poly(lactic acid) (PLA) and poly(butylene succinate) (PBS) and fillers to granules for possible marketable formulations. Different screw designs, compatibilizers and the use of glycerol as a thermoplasticization agent for SBP were also tested. The spherical, cubic, or ellipsoidal-like shaped particles of SBP are not suitable for usage as a fiber-like reinforcement. In addition, the fineness of ground SBP affects the mechanical properties because (i) a high proportion of polar surfaces leads to poor compatibility, and (ii) due to the inner structure of the particulate matter, the strength of the composite is limited to the cohesive strength of compressed sugar-cell compartments of the SBP. The compatibilization of the polymer–matrix–particle interface can be achieved by using compatibilizers of different types. Scanning electron microscopy (SEM) fracture patterns show that the compatibilization can lead to both well-bonded particles and cohesive fracture patterns in the matrix. Nevertheless, the mechanical properties are limited by the impact and elongation behavior. Therefore, the applications of SBP-based composites must be well considered.

Morphology and Mechanical Properties of Poly(Lactic Acid) and Propylene-Ethylene Copolymer Blends: Effect of Organoclay Types

2017 ◽  
Vol 737 ◽  
pp. 269-274
Author(s):  
Sirirat Wacharawichanant ◽  
Chaninthon Ounyai ◽  
Ployvaree Rassamee
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Tensile Properties ◽  
Polymer Matrix ◽  
Poly Lactic Acid ◽  
Dispersed Phase ◽  
Copolymer Blends ◽  
Morphology Analysis ◽  
Ethylene Copolymer ◽  
Morphology And Mechanical Properties

The effects of four types of organoclay on morphology and mechanical properties of poly(lactic acid) (PLA)/propylene-ethylene copolymer (PEC) blends were investigated. The ratio of PLA and PEC was 80/20 by weight and the organoclay content was 5 phr. The morphology analysis showed that the addition of all oganocaly types could improve the miscibility of PLA and PEC blends due to the decreased of the domain sizes of PEC dispersed phase in the polymer matrix. The tensile properties showed Young’s modulus of the PLA/PEC blends was improved after adding clay treated surface with 25-30 wt% trimethyl stearyl ammonium.

scholarly journals Effect of Silane Functionalization on Properties of Poly(Lactic Acid)/Palygorskite Nanocomposites

Inorganics ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 3
Author(s):  
Anton Kasprzhitskii ◽  
Georgy Lazorenko ◽  
Alexander Kruglikov ◽  
Irina Kuchkina ◽  
Vadim Gorodov
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Polymer Matrix ◽  
Covalent Bond ◽  
Poly Lactic Acid ◽  
Hydroxyl Groups ◽  
Good Dispersion ◽  
Melt Compounding

Poly(lactic acid) (PLA)/palygorskite (Paly) nanocomposites were prepared using the melt compounding technique. Paly modified by 3-aminopropyltriethoxysilane (APTES) and vinyltrimethoxysilane (VTMS) was used as nanofiller for PLA with concentrations in the 1–7 wt% range. It has been found that the functionalization allows a covalent bond between the hydroxyl groups of the Paly and the PLA matrix, evidenced by the improvement in mechanical properties. Paly modification with VTMS has better properties compared with Pale modification with APTES. This indicates a better adhesion between the Paly-VTMS and PLA matrix, and a good dispersion of the nanofiller in the polymer matrix.

scholarly journals The combined plasticization of jute and tung oil anhydride for jute fiber reinforced poly(lactic acid) composites

2021 ◽  
pp. 096739112110576
Author(s):  
Ying Zhou ◽  
Can Chen ◽  
Lan Xie ◽  
Xiaolang Chen ◽  
Guangqiang Xiao ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Physical And Mechanical Properties ◽  
Complex Viscosity ◽  
Poly Lactic Acid ◽  
Melt Blending ◽  
Sem Images ◽  
Pseudoplastic Fluid ◽  
Tung Oil ◽  
Biodegradable Poly ◽  
The Impact

In this work, novel plasticizing biodegradable poly (lactic acid) (PLA) composites were prepared by melt blending of jute and tung oil anhydride (TOA), and the physical and mechanical properties of PLA/jute/TOA composites were tested and characterized. The impact strength of PLA/jute/TOA composites significantly increases with increasing the content of TOA. The SEM images of fracture surface of PLA/jute/TOA composites become rough after the incorporation of TOA. In addition, TOA changes the crystallization temperature and decomposition process of PLA/jute/TOA composites. With increasing the amount of TOA, the value of storage modulus (E′) of PLA/jute/TOA composites gradually increases. The complex viscosity (η*) values for all samples reduce obviously with increasing the frequency, which means that the pure PLA and PLA/jute/TOA composites is typical pseudoplastic fluid. This is attributed to the formation of crosslinking, which restricts the deformation of the composites.

Sign in / Sign up

Export Citation Format

Share Document