Poly(lactic acid) phase transitions in the presence of nano calcium carbonate: Opposing effect of nanofiller on static and dynamic measurements

2018 ◽  
Vol 32 (3) ◽  
pp. 312-327 ◽  
Author(s):  
Omid Yousefzade ◽  
Javad Jeddi ◽  
Elham Vazirinasab ◽  
Hamid Garmabi
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Calcium Carbonate ◽  
Mechanical Analysis ◽  
Polymer Chains ◽  
Poly Lactic Acid ◽  
Modulated Dsc ◽  
Scanning Calorimetry ◽  
Chain Mobility ◽  
Dispersion State

The effect of stearic acid-coated nano calcium carbonate (NCC) on transitions and chain mobility of poly(lactic acid) (PLA) was investigated. Dispersion state of NCC in polymeric matrix was explored using scanning electron microscopy and surface tension component measurements. Trends of PLA transitional phenomena were investigated using the results of dynamical mechanical analysis (DMA) and differential scanning calorimetry (DSC) in the nanocomposite systems based on PLA and NCC. In addition, two types of crystal structures and decreasing the glass transition temperature were distinguished using temperature-modulated DSC (TMDSC). Higher melting points of polymer crystals were found in TMDSC experiments due to low and dynamic heating rate compared to the conventional DSC. Dynamics of polymer chains, affected by NCC, were quantified using cooperativity length, ξ α, and the number of relaxing structural units, Nα, in the glass transition region. NCC particles hindered the cooperative motion of polymer chains at glass transitions and crystallization in TMDSC measurements, whereas the DMA results indicated that NCC particles may act as lubricant and simplified chain mobility.

scholarly journals Bio-composites for Fused Filament Fabrication. Effects of Maleic Anhydride Grafting on Poly(Lactic Acid) and Microcellulose

2021 ◽  
Author(s):  
Daniele Rigotti ◽  
Luca Fambri ◽  
Alessandro Pegoretti
Keyword(s):  
Lactic Acid ◽  
Maleic Anhydride ◽  
Nucleating Agent ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Crystalline Cellulose ◽  
Fused Filament Fabrication ◽  
Scanning Calorimetry ◽  
Electron Microscopy Analysis ◽  
Reactive Mixing

Abstract Composite filaments consisting of poly(lactic acid) (PLA) and micro crystalline cellulose (MCC) were successfully used for additive manufacturing (AM) by fused filament fabrication (FFF). PLA and MCC bio-composites were obtained by direct mixing in a melt compounder; maleic anhydride (MAH) was also grafted onto PLA in reactive mixing stage to evaluate its effect on the final properties of the printed material. Filaments with various concentrations of MCC (up to a maximum content of 10 wt%) were produced with a single screw extruder and used to feed a commercial desktop FFF printer. Upon grafting of PLA with MAH, a more coherent interfacial morphology between PLA and MCC was detected by electron microscopy analysis. The thermal degradation of the PLA was unaffected by the presence of MCC and MAH. According to differential scanning calorimetry and dynamic mechanical analysis results, micro-cellulose acted as nucleating agent for PLA. In fact, the crystallization peak shifted towards lowers temperature and a synergistic effect when MCC was added to PLA grafted with MAH was observed possibly due to the increase of the chain mobility. Micro cellulose led to an increase in the stiffness of the material in both filaments and 3D printed specimen, however, a different fracture behavior was observed due to the peculiar structure of printed samples.

scholarly journals Influence of the Lignin Content on the Properties of Poly(Lactic Acid)/lignin-Containing Cellulose Nanofibrils Composite Films

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1013 ◽  
Author(s):  
Xuan Wang ◽  
Yuan Jia ◽  
Zhen Liu ◽  
Jiaojiao Miao
Keyword(s):  
Lactic Acid ◽  
Lignin Content ◽  
Cellulose Nanofibrils ◽  
Composite Films ◽  
Tensile Tests ◽  
Nucleating Agent ◽  
Mechanical Analysis ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry

Poly(lactic acid) (PLA)/lignin-containing cellulose nanofibrils (L-CNFs) composite films with different lignin contents were produced bythe solution casting method. The effect of the lignin content on the mechanical, thermal, and crystallinity properties, and PLA/LCNFs interfacial adhesion wereinvestigated by tensile tests, thermogravimetric analysis, differential scanning calorimetry (DSC), dynamic mechanical analysis, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The tensile strength and modulus of the PLA/9-LCNFs (9 wt % lignin LCNFs) composites are 37% and 61% higher than those of pure PLA, respectively. The glass transition temperature (Tg) decreases from 61.2 for pure PLA to 52.6 °C for the PLA/14-LCNFs (14 wt % lignin LCNFs) composite, and the composites have higher thermal stability below 380 °C than pure PLA. The DSC results indicate that the LCNFs, containing different lignin contents, act as a nucleating agent to increase the degree of crystallinity of PLA. The effect of the LCNFs lignin content on the PLA/LCNFs compatibility/adhesion was confirmed by the FTIR, SEM, and Tg results. Increasing the LCNFs lignin content increases the storage modulus of the PLA/LCNFs composites to a maximum for the PLA/9-LCNFs composite. This study shows that the lignin content has a considerable effect on the strength and flexibility of PLA/LCNFs composites.

Structure and properties of poly(lactic acid)/poly(lactic acid)-α-cyclodextrin inclusion compound composites

2017 ◽  
Vol 37 (9) ◽  
pp. 897-909
Author(s):  
Li Zhang ◽  
Weijun Zhen ◽  
Yufang Zhou
Keyword(s):  
Lactic Acid ◽  
Average Molecular Weight ◽  
Gel Permeation Chromatography ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Polymerization Temperature ◽  
Scanning Calorimetry ◽  
Synthesis Conditions ◽  
Cyclodextrin Inclusion ◽  
Comprehensive Performance

Abstract Poly(lactic acid) (PLA) was synthesized using a green catalyst, nano-zinc oxide (ZnO). The optimum synthesis conditions of PLA were as follows: a stoichiometric amount of 0.5 wt% of nano-ZnO, polymerization time of 14 h, and polymerization temperature of 170°C. Gel permeation chromatography results showed that the weight-average molecular weight (Mw) of PLA was 13,072 g/mol with a polydispersity index (PDI) of 1.7. Furthermore, PLA-α-cyclodextrin inclusion compounds (PLA-CD-ICs) were prepared by ultrasonic co-precipitation techniques. X-ray diffraction analysis and Fourier transform infrared spectroscopy demonstrated the change in lattice of α-CD from a cage configuration to a tunnel structure and the existence of some physical interactions between α-CD and PLA in the PLA-CD-ICs. To enhance the crystallization properties of PLA, PLA/PLA-CD-IC composites were blended with different contents of PLA-CD-ICs as nucleating agents. The crystallization behavior and comprehensive performance were investigated by differential scanning calorimetry, polarized optical microscopy, tensile testing, dynamic mechanical analysis, and scanning electron microscopy. Compared to PLA, the crystallinities of PLA/PLA-CD-IC composites were increased by 24.0%, 26.3%, 27.3%, and 31.8%. The results of all the analyses proved that PLA-CD-ICs were useful as green organic nucleators and improved the comprehensive performance of PLA materials.

scholarly journals Thermal and Dynamic Mechanical Analyses of Poly(Lactic Acid)/Poly(Ethylene Glycol) Blends

2018 ◽  
Vol 1 (1) ◽  
pp. 526-535
Author(s):  
Benaniba Mohamed Tahar ◽  
Aouachria Kamira
Keyword(s):  
Lactic Acid ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Ethylene Glycol ◽  
Poly Lactic Acid ◽  
Poly Ethylene Glycol ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Poly Ethylene

Blends of poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) with various contents (0, 5, 10, 15, 20 and 30 weight %) and with different molecular weights (M¯w = 1000, 4000 and 6000 g/mol), called respectively PEG1, PEG2, and PEG3 were prepared by melt blending. Since glass transition temperature (Tg), T? and loss factor (tan ?) are relevant indicators of polymer chain mobility, plasticization has been studied by dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). Low molecular weight (LMW) PEG enable increased miscibility with PLA and more efficient reduction of glass transition temperature (Tg) for concentrations of PEG less than 20%. This effect is not only enhanced by the LMW but also by increasing its content up to 20%. As expected, both T? and Tg decrease when increasing PEG molar mass and content up to 20%, which demonstrates the effectiveness of PEG to act as a plasticizer of PLA.

scholarly journals Thermal and Structural Analysis of Epoxidized Jatropha Oil and Alkaline Treated Kenaf Fiber Reinforced Poly(Lactic Acid) Biocomposites

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2604
Author(s):  
Siti Hasnah Kamarudin ◽  
Luqman Chuah Abdullah ◽  
Min Min Aung ◽  
Chantara Thevy Ratnam
Keyword(s):  
Lactic Acid ◽  
Thermal Properties ◽  
Alkaline Treatment ◽  
Poly Lactic Acid ◽  
Jatropha Oil ◽  
Scanning Calorimetry ◽  
Kenaf Fiber ◽  
Chain Mobility ◽  
Naoh Solution ◽  
Thermal Stability Of

New environmentally friendly plasticized poly(lactic acid) (PLA) kenaf biocomposites were obtained through a melt blending process from a combination of epoxidized jatropha oil, a type of nonedible vegetable oil material, and renewable plasticizer. The main objective of this study is to investigate the effect of the incorporation of epoxidized jatropha oil (EJO) as a plasticizer and alkaline treatment of kenaf fiber on the thermal properties of PLA/Kenaf/EJO biocomposites. Kenaf fiber was treated with 6% sodium hydroxide (NaOH) solution for 4 h. The thermal properties of the biocomposites were analyzed using a differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). It must be highlighted that the addition of EJO resulted in a decrease of glass transition temperature which aided PLA chain mobility in the blend as predicted. TGA demonstrated that the presence of treated kenaf fiber together with EJO in the blends reduced the rate of decomposition of PLA and enhanced the thermal stability of the blend. The treatment showed a rougher surface fiber in scanning electron microscopy (SEM) micrographs and had a greater mechanical locking with matrix, and this was further supported with Fourier-transform infrared spectroscopy (FTIR) analysis. Overall, the increasing content of EJO as a plasticizer has improved the thermal properties of PLA/Kenaf/EJO biocomposites.

scholarly journals Miscibility study of solution cast blends of poly(lactic acid) and poly(vinyl butyral)

2005 ◽  
Vol 23 (1) ◽  
pp. 22 ◽  
Author(s):  
J R Khurma ◽  
D R Rohindra ◽  
R Devi
Keyword(s):  
Lactic Acid ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Casting Method ◽  
Scanning Calorimetry ◽  
Appreciable Change ◽  
Solution Cast ◽  
Solution Casting Method ◽  
The Common ◽  
Vinyl Butyral

Poly(lactic acid) (PLA) was blended with poly(viny1 butyral) (PVB) through solution casting method using chloroform as the common solvent. The films obtained were characterized for miscibility using Differential Scanning Calorimetry (DSC), tensile testing and FTIR spectroscopy. The DSC results showed that the glass-transition temperature (Tg) of the PLA and PVB remained more or less constant with the composition of the blend. The existence of two Tg?s in the blends indicated that PLA and PVB were immiscible over the composition range investigated. percentage crystallinity ( cc ), of PLA phase remained constant with increasing PVB content in the blend. FTIR measurements showed that there was no appreciable change in the spectra with respect to blend composition, implying the immiscibility of the two polymers. Mechanical analysis showed that the tensile strength and elongation decreased on blending.

Plasticizing effects of citrate esters on properties of poly(lactic acid)

2016 ◽  
Vol 36 (4) ◽  
pp. 371-380 ◽  
Author(s):  
Mounira Maiza ◽  
Mohamed Tahar Benaniba ◽  
Valérie Massardier-Nageotte
Keyword(s):  
Differential Scanning Calorimetry ◽  
Lactic Acid ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Triethyl Citrate ◽  
Acetyl Tributyl Citrate

Abstract Triethyl citrate (TEC) and acetyl tributyl citrate (ATBC) were used as plasticizer for poly(lactic acid) (PLA). The treated and plasticized PLA at various concentrations were analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and opacity. DSC was used to evaluate the crystallinity and thermal property of all the samples. It was found that the glass transition temperature (Tg) and the melting temperature (Tm) decreased as the amount of citrate esters increased. Additionally, the presence of TEC or ATBC tended to increase the crystallinity of PLA. This result was supported by XRD. DMA of plasticized PLA indicates that a decrease in Tg is obtained with increasing plasticizer content. FTIR spectra indicate that there are some molecular interactions by intermolecular hydrogen bonds between PLA and citrate esters. The effect of the concentration of plasticizer on the opacity of the films was negligible.

scholarly journals Poly(ε-Caprolactone)/Poly(Lactic Acid) Blends Compatibilized by Peroxide Initiators: Comparison of Two Strategies

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 228 ◽  
Author(s):  
Marta Przybysz-Romatowska ◽  
Józef Haponiuk ◽  
Krzysztof Formela
Keyword(s):  
Lactic Acid ◽  
Melt Flow Index ◽  
Mechanical Analysis ◽  
Poly Lactic Acid ◽  
Flow Index ◽  
Infrared Spectrometry ◽  
Thermal And Mechanical Properties ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
Reaction In Solution

Poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) blends were compatibilized by reactive blending and by copolymers formed during reaction in the solution. The reactive blending of PCL/PLA was performed using di-(2-tert-butyl-peroxyisopropyl)benzene (BIB) or dicumyl peroxide (DCP) as radical initiator. PCL-g-PLA copolymers were prepared using 1.0 wt. % of DCP or BIB via reaction in solution, which was investigated through a Fourier transform infrared spectrometry (FTIR) and nuclear magnetic resonance (NMR) in order to better understand the occurring mechanisms. The effect of different additions such as PCL-g-PLA copolymers, DCP, or BIB on the properties of PCL/PLA blends was studied. The unmodified PCL/PLA blends showed a sea-island morphology typical of incompatible blends, where PLA droplets were dispersed in the PCL matrix. Application of organic peroxides improved miscibility between PCL and PLA phases. A similar effect was observed for PCL/PLA blend compatibilized by PCL-g-PLA copolymer, where BIB was used as initiator. However, in case of application of the peroxides, the PCL/PLA blends were cross-linked, and it has been confirmed by the gel fraction and melt flow index measurements. The thermal and mechanical properties of the blends were also investigated by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and tensile strength.

scholarly journals The Effects of Chain-Extending Cross-Linkers on the Mechanical and Thermal Properties of Poly(butylene adipate terephthalate)/Poly(lactic acid) Blown Films

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3092
Author(s):  
Juliana V. C. Azevedo ◽  
Esther Ramakers-van Dorp ◽  
Berenika Hausnerova ◽  
Bernhard Möginger
Keyword(s):  
Mechanical Performance ◽  
Synergetic Effect ◽  
Mechanical Analysis ◽  
Polymer Chains ◽  
Poly Lactic Acid ◽  
Mechanical And Thermal Properties ◽  
Film Blowing ◽  
Scanning Calorimetry ◽  
Dsc Measurements ◽  
Seal Strength

This study investigates the effects of four multifunctional chain-extending cross-linkers (CECL) on the processability, mechanical performance, and structure of polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA) blends produced using film blowing technology. The newly developed reference compound (M·VERA® B5029) and the CECL modified blends are characterized with respect to the initial properties and the corresponding properties after aging at 50 °C for 1 and 2 months. The tensile strength, seal strength, and melt volume rate (MVR) are markedly changed after thermal aging, whereas the storage modulus, elongation at the break, and tear resistance remain constant. The degradation of the polymer chains and crosslinking with increased and decreased MVR, respectively, is examined thoroughly with differential scanning calorimetry (DSC), with the results indicating that the CECL-modified blends do not generally endure thermo-oxidation over time. Further, DSC measurements of 25 µm and 100 µm films reveal that film blowing pronouncedly changes the structures of the compounds. These findings are also confirmed by dynamic mechanical analysis, with the conclusion that tris(2,4-di-tert-butylphenyl)phosphite barely affects the glass transition temperature, while with the other changes in CECL are seen. Cross-linking is found for aromatic polycarbodiimide and poly(4,4-dicyclohexylmethanecarbodiimide) CECL after melting of granules and films, although overall the most synergetic effect of the CECL is shown by 1,3-phenylenebisoxazoline.

scholarly journals Water barrier and mechanical properties of sugar palm crystalline nanocellulose reinforced thermoplastic sugar palm starch (TPS)/poly(lactic acid) (PLA) blend bionanocomposites

2021 ◽  
Vol 10 (1) ◽  
pp. 431-442
Author(s):  
Asmawi Nazrin ◽  
Salit Mohd Sapuan ◽  
Mohamed Yusoff Mohd Zuhri ◽  
Intan Syafinaz Mohamed Amin Tawakkal ◽  
Rushdan Ahmad Ilyas
Keyword(s):  
Lactic Acid ◽  
Food Packaging ◽  
Water Vapor Permeability ◽  
Mechanical Analysis ◽  
Polymer Chains ◽  
Poly Lactic Acid ◽  
Vapor Permeability ◽  
Toxic Substances ◽  
Plastic Wastes ◽  
Recycled Plastics

Abstract The disposal of non-biodegradable synthetic plastic wastes is linked with air, land, and marine pollutions. Incineration of plastic wastes released toxic substances into the air while recycled plastics end up accumulated in landfill and dumped into the ocean. In this study, novel sugar palm starch reinforced with sugar palm crystalline nanocellulose was blended with poly(lactic acid) (PLA) with various formulations to develop alternative materials potentially substituting conventional plastics. X-ray diffraction analysis demonstrated broad amorphous scattering background with minor diffraction peaks at 2θ of 19.4° and 22° associated with VH-type and B-type crystal structure for all blend bionanocomposites samples. Higher solubility rates were observed for PLA20TPS80 (96.34%) and PLA40TPS60 (77.66%) associated with higher concentration of plasticizers providing extra space in the polymer chains to be penetrated by water molecules. Increasing PLA content was not necessarily enhancing the water vapor permeability rate. Dynamic mechanical analysis presented a significant increment in storage modulus (E′) for PLA60TPS40 (53.2%) compared to the trivial changes of PLA70TPS30 (10%) and PLA80TPS20 (0.6%). However, significant improvement in impact strength occurred only at PLA40TPS60 (33.13%), and further addition showed minor improvement between 12 and 20%. Overall, it is noted that PLA60TPS40 demonstrated adequate functional properties to be used in food packaging application.

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