Utilization of Talc as a Nucleating Agent in Poly(Lactic Acid) and Poly(Butylene Succinate) Blend

2021 ◽  
Vol 1046 ◽  
pp. 105-110
Author(s):  
Nawadon Petchwattana ◽  
Kittisak Promsuk ◽  
Junnapat Rabuepin ◽  
Phoempol Siangdang
Keyword(s):  
Lactic Acid ◽  
Injection Molding ◽  
Tensile Elongation ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Experimental Results ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Injection Molding Process ◽  
Butylene Succinate

In this paper, poly(lactic acid) (PLA) was modified with poly(butylene succinate) (PBS) and talc to obtain PLA formulation with good toughness and high crystallization rate. PBS was added as a toughening agent at 40wt% and talc was added as a nucleating agent from 2 to 10wt%. Experimental results showed that both the tensile modulus and strength of PLA significantly decreased with the presence of PBS. Both values were found to notably increase with talc concentration and reached the maximum value at 8wt%. The tensile elongation at break was found to remarkably increase with PBS blending. However, it was linearly dropped with talc addition. Thermal test results also indicated the faster crystallization rate with the decreased crystallization temperature (Tc) and increased degree of crystallinity (Xc), by more than four times, when talc was added at least 4wt%. The isothermal crystallization half-time (t1/2) was applied to provide the data for injection molding process. The results showed that neat PLA required more than 25 min to obtain its half crystallinity. Minimum t1/2 of 3.45 min was obtained when talc was added to PLA/PBS at 8wt%. Heat distortion temperature (HDT) was also found to increase from 56.8 (neat PLA) to 97.2°C (8wt% talc). Based on the experimental results, the optimum talc concentration was 8wt% which provided the highest crystallization rate and thermal stability. The practical application of this formulation is for the biodegradable injection molding products.

Effect of Poly(D-Lactic Acid)-co-Polyethylene Glycol on the Crystallization of Poly(L-Lactic Acid)

2017 ◽  
Vol 751 ◽  
pp. 283-289 ◽  
Author(s):  
Ployrawee Kaewlamyai ◽  
Amornrat Lertworasirikul
Keyword(s):  
Lactic Acid ◽  
Polyethylene Glycol ◽  
Weight Ratio ◽  
Crystallization Rate ◽  
Heat Stability ◽  
Nucleating Agent ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry

Poly (lactic acid) (PLA) is a biopolymer derived from renewable resources and can be disposed of without creating harm to the environment. PLA can be formed by thermoplastic processes and has good mechanical properties. However, its disadvantages are a high crystallization temperature, slow crystallization rate, poor heat stability and low ductility. In the past, it was found that poly (D-lactic acid) (PDLA) can form complexes with poly (L-lactic acid) (PLLA) and the complexes could accelerate the crystallization and increase the degree of crystallinity of the PLA, but decrease the ductility. It is known that polyethylene glycol (PEG) can improve the ductility of PLLA. In this research, PDLA was copolymerized with PEG in an attempt to improve both crystallization behavior and ductility of PLLA. Poly (D-lactic acid)-co-polyethylene glycol (PDEG) was synthesized by ring opening polymerization using D-lactide and PEG at a D-lactide:PEG weight ratio of 10:3. The PDEG was blended with PLLA with a PDEG content of 0wt% to 50wt% by melt blending process. Fourier transform infrared spectrometry (FT-IR) and X-Ray diffractometry (XRD) confirmed the stereocomplex formation between PDEG and PLLA. Characterization by differential scanning calorimetry (DSC) revealed that crystallization temperatures of the blends were decreased in the presence of PDEG. Storage moduli and tan of the blends obtained from dynamic mechanical analysis (DMA) decreased as PDEG content increased. Polarized optical microscopy (POM) micrographs of blends with PDEG content of 1wt% to 5wt% obviously showed that crystallization rate was increased. PDEG has the potential to be an effective nucleating agent and efficient plasticizer for PLLA.

Influence of temperature dependence on the structural characteristics of polyoxymethylene/poly(lactic acid) blends by injection molding

2019 ◽  
Vol 39 (10) ◽  
pp. 944-953
Author(s):  
Jitlada Boonlertsamut ◽  
Suchalinee Mathurosemontri ◽  
Supaphorn Thumsorn ◽  
Toshikazu Umemura ◽  
Atsushi Sakuma
Keyword(s):  
Lactic Acid ◽  
Injection Molding ◽  
Crystal Size ◽  
Structural Characteristics ◽  
Growth Direction ◽  
Poly Lactic Acid ◽  
Injection Molding Process ◽  
Mechanical And Thermal Properties ◽  
Molding Process ◽  
Microscopy Images

Abstract In this research, different strategies to modify the structure of polymer blends were investigated with the objective of adjusting the composition of polyoxymethylene (POM) and poly(lactic acid) (PLA) under typical processing conditions. POM shows a good balance of mechanical and thermal properties. However, this polymer is obtained from petrochemical sources, and in some markets, environmentally friendly materials are important. Blending POM with PLA preserves the advantages of POM while ensuring the bio-based content of PLA. POM/PLA blends were prepared by an injection molding process with various injection speeds of 10, 50, 100, and 1000 mm/s to ensure high ductility. Mechanical property analysis showed that the PLA content and processing temperatures are highly effective in modifying the stiffness of POM/PLA blends. The effect of crystallization on POM/PLA blends was assessed by varying the annealing time. High-magnification scanning electron microscopy images revealed that the gaps between fibrillar regions represent the growth direction of the PLA phase before it was removed. This was evidence for the effect of PLA on the crystallization of POM. The crystal size and crystalline volume also affected the structural characteristics of POM/PLA blends.

scholarly journals Crystallization Kinetics of Poly(lactic acid)–Graphene Nanoscroll Nanocomposites: Role of Tubular, Planar, and Scrolled Carbon Nanoparticles

2021 ◽  
Vol 7 (4) ◽  
pp. 75
Author(s):  
Oluwakemi Ajala ◽  
Caroline Werther ◽  
Rauf Mahmudzade ◽  
Peyman Nikaeen ◽  
Dilip Depan
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Crystallization Kinetics ◽  
Crystallization Rate ◽  
Melting Behavior ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Avrami Model ◽  
Superior Mechanical Properties ◽  
Kinetics Of

Graphene nanoscrolls (GNS) are 1D carbon-based nanoparticles. In this study, they were investigated as a heterogeneous nucleating agent in the poly(lactic acid) (PLA) matrix. The isothermal and non-isothermal melting behavior and crystallization kinetics of PLA-GNS nanocomposites were investigated using a differential scanning calorimeter (DSC). Low GNS content not only accelerated the crystallization rate, but also the degree of crystallinity of PLA. The Avrami model was used to fit raw experimental data, and to evaluate the crystallization kinetics for both isothermal and non-isothermal runs through the nucleation and growth rate. Additionally, the effect of the dimensionality and structure of the nanoparticle on the crystallization behavior and kinetics of PLA is discussed. GNS, having a similar fundamental unit as CNT and GNP, were observed to possess superior mechanical properties when analyzed by the nanoindentation technique. The scrolled architecture of GNS facilitated a better interface and increased energy absorption with PLA compared to CNTs and GNPs, resulting in superior mechanical properties.

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.

scholarly journals Interfacial Adhesive Strength of Two Layered Polyoxymethylene/Poly (lactic acid) Molding by a Simultaneous Composite Injection Molding Process

Seikei-Kakou ◽  
2011 ◽  
Vol 23 (9) ◽  
pp. 561-567
Author(s):  
Satoshi Nagai ◽  
Akira Itou ◽  
Wongsriraksa Patcharat ◽  
Supaporn Thumsorn ◽  
Yew Wei Leong ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Injection Molding ◽  
Adhesive Strength ◽  
Poly Lactic Acid ◽  
Injection Molding Process ◽  
Molding Process

Non-isothermal crystallization kinetics of poly (lactic acid)/graphene nanocomposites

2013 ◽  
Vol 33 (2) ◽  
pp. 163-171 ◽  
Author(s):  
Yanhua Chen ◽  
Xiayin Yao ◽  
Qun Gu ◽  
Zhijuan Pan
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Graphene Nanocomposites ◽  
Solution Blending ◽  
Transmission Electron ◽  
Graphene Nanocomposite

Abstract Poly(lactic acid) (PLA)/graphene nanocomposites were prepared by solution blending and the dispersibility of graphene in the PLA matrix was examined by transmission electron microscopy (TEM). The non-isothermal crystallization behaviors of pure PLA and PLA/graphene nanocomposites from the melt were investigated by differential scanning calorimetry (DSC). The results showed that the graphene could play a role as a heterogeneous nucleating agent during the non-isothermal crystallizing process of PLA, and accelerate the crystallization rate. The non-isothermal crystallizing data were analyzed with the Avrami, Ozawa and Mo et al. models and the crystallization parameters of the samples were obtained. It is demonstrated that the combination of the Avrami and Ozawa models developed by Mo et al. was successful in describing the non-isothermal crystallization process for pure PLA and its nanocomposite. According to the Kissinger equation, the activation energies were found to be -154.3 and -179.5 kJ/mol for pure PLA and PLA/0.1 wt% graphene nanocomposite, respectively. Furthermore, the spherulite growth behavior was investigated by polarized optical microscopy (POM) and the results also supported the DSC data.

Blending and plasticising effects on the behaviour of poly(lactic acid)/poly(ε-caprolactone)

2018 ◽  
Vol 26 (5-6) ◽  
pp. 337-345 ◽  
Author(s):  
Nesrine Khitas ◽  
Kamira Aouachria ◽  
Mohamed Tahar Benaniba
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Nucleating Agent ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Triethyl Citrate ◽  
Acetyl Tributyl Citrate ◽  
The Degree Of Crystallinity

Polymer blending is one of the most convenient methods to be used to overcome the limitations of some single properties of polymers and to achieve the combinations required for specific applications. Another feasible common practice is the incorporation of additives of low molecular weight such as plasticisers to impart flexibility, improve toughness and lower the glass transition temperature ( Tg). This study focused on the effects of blending and plasticising on the crystallisation behaviour of poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL). PCL with longer degradation time compared with other polymers was blended with PLA to overcome the limitation of its brittleness and poor thermal stability. Acetyl tributyl citrate (ATBC) and acetyl triethyl citrate (TEC) were used as plasticiser in PLA/PCL blends. The rigid and plasticised blends at various ratios were analysed by differential scanning calorimetry, thermogravimetric analysis and X-ray diffraction. The results revealed a slight increase in the degree of crystallinity and a significant increase in the Tg of PLA due to the addition of PCL. The addition of ATBC has promoted a decrease in thermal stability of the blends. The slight increase in the degree of crystallinity suggested that PCL acted as a nucleating agent. The citrate plasticisers were shown to lower the Tg and have much more enhanced the crystallisation of PLA. Moreover, the rigid and plasticised blends were shown to be partially miscible.

Crystallization Behavior of Vetiver Grass Fiber-Polylactic Acid Composite

2011 ◽  
Vol 410 ◽  
pp. 55-58 ◽  
Author(s):  
Somruetai Boonying ◽  
Wimonlak Sutapun ◽  
Nitinat Suppakarn ◽  
Yupaporn Ruksakulpiwat
Keyword(s):  
Crystallization Behavior ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Fiber Content ◽  
Degree Of Crystallinity ◽  
Poly Lactic Acid ◽  
Vetiver Grass ◽  
Equilibrium Melting Temperature ◽  
Crystallization Degree ◽  
Nucleating Effect

this work, vetiver fiber was used as a filler for poly (lactic acid) (PLA). The thermal properties of neat PLA and vetiver fiber-PLA composites were investigated. Talc as a nucleating agent was used to compare the nucleating effect on crystallization of the composites from vetiver fiber. It was found that crystallization rate was highest in the case of talc-PLA composites. Beside, the crystallization rate of PLA with 20%vetiver fiber content was higher than that of neat PLA and 1-10% (w/w) vetiver fiber-PLA composites. The equilibrium melting temperature (T0m) of neat PLA and PLA composites was obtained from Hoffman-Weeks plot. It was found that the presence of vetiver fiber and talc caused T0m values of PLA decreased compared to that of neat PLA. In addition, T0m values of PLA decreased with increasing vetiver fiber content. For non-isothermal crystallization, degree of crystallinity ( %XC )increased with the presence of vetiver fiber compared to that of neat PLA. As vetiver fiber content increased, %XC increased. Similarly, the incorporation of talc led to an increase in %XC compared to that of neat PLA. PLA with 1%talc content showed the highest %XCcompared to neat PLA and other PLA composites. Moreover, %XC decreased with increasing talc content.

Crystallization Behaviors of Plasticized Poly(Lactic Acid)/Microcrystalline Cellulose Composite Sheet

2020 ◽  
Vol 856 ◽  
pp. 303-308
Author(s):  
Suttinun Phongtamrug ◽  
Sirisart Ouajai
Keyword(s):  
Lactic Acid ◽  
Microcrystalline Cellulose ◽  
Testing Machine ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Twin Screw

Poly(lactic acid) (PLA) is a potential biodegradable polymer to replace petroleum-based plastic, however, its main drawback is brittleness because of slow crystallization rate. To overcome this limitation, compounding with some additives is the most chosen choice due to easy and effective preparation. In this study, an epoxidized soybean oil (ESO) and a microcrystalline cellulose (MCC) were applied as a plasticizer and a nucleating agent, respectively. The PLA was compounded with ESO and MCC by using a twin-screw extruder. The product sheets were prepared by using a chill-roll cast film extruder. Change of thermal property after adding ESO and MCC was investigated by a differential scanning calorimeter. Mechanical property of the prepared sheet was carried out by using a universal testing machine in a tensile mode. Microstructure of the sheets was also studied by wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS) techniques. The results showed that ESO assisted plasticization while the MCC induced crystallization of PLA. Also, ESO and MCC eased flowability and alignment of PLA microstructure in machine direction.

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