scholarly journals Combined Effects of Cellulose Nanofiber Nucleation and Maleated Polylactic Acid Compatibilization on the Crystallization Kinetic and Mechanical Properties of Polylactic Acid Nanocomposite

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3226
Author(s):  
Siti Shazra Shazleen ◽  
Lawrence Yee Foong Ng ◽  
Nor Azowa Ibrahim ◽  
Mohd Ali Hassan ◽  
Hidayah Ariffin

This work investigated the combined effects of CNF nucleation (3 wt.%) and PLA-g-MA compatibilization at different loadings (1–4 wt.%) on the crystallization kinetics and mechanical properties of polylactic acid (PLA). A crystallization kinetics study was done through isothermal and non-isothermal crystallization kinetics using differential scanning calorimetry (DSC) analysis. It was shown that PLA-g-MA had some effect on nucleation as exhibited by the value of crystallization half time and crystallization rate of the PLA/PLA-g-MA, which were increased by 180% and 172%, respectively, as compared to neat PLA when isothermally melt crystallized at 100 °C. Nevertheless, the presence of PLA-g-MA in PLA/PLA-g-MA/CNF3 nanocomposites did not improve the crystallization rate compared to that of uncompatibilized PLA/CNF3. Tensile strength was reduced with the increased amount of PLA-g-MA. Contrarily, Young’s modulus values showed drastic increment compared to the neat PLA, showing that the addition of the PLA-g-MA contributed to the rigidity of the PLA nanocomposites. Overall, it can be concluded that PLA/CNF nanocomposite has good performance, whereby the addition of PLA-g-MA in PLA/CNF may not be necessary for improving both the crystallization kinetics and tensile strength. The addition of PLA-g-MA may be needed to produce rigid nanocomposites; nevertheless, in this case, the crystallization rate of the material needs to be compromised.

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 702-709
Author(s):  
Hyeong Min Yoo ◽  
Su-Yeon Jeong ◽  
Sung-Woong Choi

Abstract The aim of this study was to determine the rheological property and crystallization behavior of polylactic acid (PLA) with improved heat resistance (Ingeo™ Biopolymer 4032D) through investigation of the melt viscosity and crystallization kinetics of PLA at different process temperatures. The viscosity was measured using a rotational rheometer under conditions of shear rates of 0.01, 0.1, and 1/s. The obtained rheological data show that the viscosity tended to decrease slightly as the shear rate increases and decrease sharply as the temperature increases from 180°C to 210°C. To investigate the effect of the process temperature on the crystallization kinetics and final crystallinity of PLA, thermal analysis using isothermal differential scanning calorimetry (DSC) were also performed. The Avrami equation was successfully applied for the isothermal crystallization kinetics model. From crystallization temperature of 85°C to 120°C, we found that the Ingeo™ Biopolymer 4032D PLA had the fastest crystallization rate (t 1/2: 26.0 min) and the largest crystallinity (47.4%) at 100°C.


2014 ◽  
Vol 915-916 ◽  
pp. 751-754
Author(s):  
Shao Hui Wang

The composites of PP/Talc modified by stearic acid were prepared and its effect on the properties of PP/Talc composites was investigated in this paper. The tensile strength and impact strength of PP/Talc composites increased about 15% and 30% compared with pure PP respectively. Based on surface analysis by scanning electron microscope (SEM), the Talcparticles buried well in PP matrix when the Talc was coated with the stearic acid. At the same time, it was found that Talc significantly increased the crystallization temperature and crystallization rate of PP by differential scanning calorimetry (DSC).


2012 ◽  
Vol 535-537 ◽  
pp. 1142-1145
Author(s):  
Guang Tian Liu ◽  
Jing Lei

In this paper, the isothermal crystallization kinetics of isotactic polypropylene (iPP) and iPP with 5% hyperbranched polymer (HBP) added had been investigated by differential scanning calorimetry (DSC). The results show that a small addition of HBP affects the crystallization behavior of iPP. During isothermal crystallization, the crystallization rate of the blend is higher than those of iPP remarkably. An increase in the Avrami exponent may be attributed to the fractal structure of hyperbranched polymer. The crystallization activation energy is estimated by the Friedman equation, the results show that the activation energy decreases remarkably by addition of HBP and the crystallization rate of the blend is more sensitive to temperature than that of iPP.


2014 ◽  
Vol 34 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Yassir A. Eltahir ◽  
Haroon A.M. Saeed ◽  
Chen Yuejun ◽  
Yumin Xia ◽  
Wang Yimin

Abstract The non-isothermal crystallization behavior of polyamide 5,6 (PA56) was investigated by differential scanning calorimeter (DSC), and the non-isothermal crystallization kinetics were analyzed using the modified Avrami equation, the Ozawa model, and the method combining the Avrami and Ozawa equations. It was found that the Avrami method modified by Jeziorny could only describe the primary stage of non-isothermal crystallization kinetics of PA56, the Ozawa model failed to describe the non-isothermal crystallization of PA56, while the combined approach could successfully describe the non-isothermal crystallization process much more effectively. Kinetic parameters, such as the Avrami exponent, kinetic crystallization rate constant, relative degree of crystallinity, the crystallization enthalpy, and activation energy, were also determined for PA56.


2013 ◽  
Vol 848 ◽  
pp. 46-49
Author(s):  
Zi Nian Zhao ◽  
Xiao Li Lei

By means of melt blending process in a co-rotating twin screw extruder and blow molding , the low density polyethylene (LDPE)/thermoplastic elastomer(TPE) mixed membranes and LDPE/inorganic particles composite membrane were prepared. by differential scanning calorimetry(DSC) to study the non-isothermal crystallization kinetics of the LDPE composite system by differential scanning calorimetry (DSC).Use modified Jeziorny method to process the data ,the results shows that ZMS, SiO2, EVA and EMAA all play a role of heterogeneous nucleation and the crystallization rate of LDPE has been increased,especially the ZMS/LDPE composite system which heterogeneous nucleation is more obvious and crystallization rate is faster.


Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1160 ◽  
Author(s):  
Chin-Wen Chen ◽  
Te-Sheng Hsu ◽  
Kuan-Wei Huang ◽  
Syang-Peng Rwei

Unsaturated poly (butylene adipate-co-butylene itaconate) (PBABI) copolyesters were synthesized through melt polymerization composed of 1,4-butanediol (BDO), adipic acid (AA), itaconic acid (IA) and 1,2,4,5-benzenetetracarboxylic acid (BTCA) as a cross-linking modifier. The melting point, crystallization and glass transition temperature of the PBABI copolyesters were detected around 29.8–49 °C, 7.2–29 °C and −51.1 and −58.1 °C, respectively. Young’s modulus can be modified via partial cross-linking by BTCA in the presence of IA, ranging between 32.19–168.45 MPa. Non-isothermal crystallization kinetics were carried out to explore the crystallization behavior, revealing the highest crystallization rate was placed in the BA/BI = 90/10 at a given molecular weight. Furthermore, the thermal, mechanical properties, and crystallization rate of PBABI copolyesters can be tuned through the adjustment of BTCA and IA concentrations.


2017 ◽  
Vol 264 ◽  
pp. 25-28
Author(s):  
Mat Taib Razaina ◽  
Cho Yin Tham

Isothermal crystallization kinetics and morphology of Poly (lactic acid) (PLA) and PLA/ethylene acrylate copolymer (EAC) blends were studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM) at various temperatures (95–125°C). The DSC data obtained was analyzed using the Avrami equation. The crystallization rate was found to depend on the crystallization temperature (Tc) and EAC content. At a given Tc, the crystallization rate value was greater in the blends than in PLA suggesting that the presence of EAC enhanced crystallization of PLA. Based on the DSC analysis the crystallization rate was maximum when PLA blend with 1 wt.% EAC was isothermally crystallized at 103°C. The presence of EAC did not significantly change in the spherulitic growth rate (G) of PLA. Analysis of the growth rates using the Lauritzen-Hoffman theory showed that a regime II to regime III transition was present for all PLA/EAC blends and that this transition occurred at temperature of 100°C. The fold surface energy values of PLA/EAC blends were lower than that of PLA indicating that PLA chains can readily fold onto the crystal nucleus surface after the incorporation of EAC.


e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Yinghong Xiao ◽  
Jianfei Che ◽  
Anne Bergeret ◽  
Chun Mao ◽  
Jian Shen

AbstractGraft modification of polylactic acid (PLA) with acrylic acid (AA) using double initiators was studied. The composition of the graft copolymer (PLA-AA) was characterized with Fourier transform infrared (FTIR) spectroscopy and introduction of AA was demonstrated. Differential scanning calorimetry (DSC) analysis indicated that due to the increasing graft efficacy the modified PLA had better interfacial adhesion with starch compared to neat PLA. Fracture surfaces of starch/PLA and starch/PLA-AA were observed using scanning electron microscope (SEM) and the results also demonstrated the better interfacial adhesion of the latter composite. Graft modification of PLA matrix and introduction of starch played important roles in enhancing the mechanical properties (strength and modulus) while remaining good degradability of the composite.


2017 ◽  
Vol 866 ◽  
pp. 208-211 ◽  
Author(s):  
Kantima Chaochanchaikul

The aim of this work was to improve the mechanical properties of polylactic acid (PLA) by natural oil polyol. Castor oil is natural oil polyol used for this work. It was directly extracted from castor seed and without chemical modification. The contents of castor oil were varied from 0 to 10 wt%. The effect of castor oil content on mechanical properties of PLA were evaluated by tensile and impact testings. Differential scanning calorimetry (DSC) and morphology analysis were used for explanation of the result. The result showed that the elongation at break and impact strength of PLA /10 wt% castor oil blend were increased about 108 and 30 % as comparing neat PLA whereas tensile strength tended to decrease about 24 %. The changes in glass transition temperature, crystallinity content and morphology of PLA corresponded well with the result of mechanical properties.


2020 ◽  
Vol 23 (8) ◽  
pp. 295-304
Author(s):  
Wida Banar Kusumaningrum ◽  
Firda Aulya Syamani ◽  
Lisman Suryanegara

Polylactic acid (PLA) is a biopolymer that can replace thermoplastic polymers such as polypropylene (PP) in various applications due to strength, young modulus, biocompatibility, biodegradability, good clarity, oil resistance, and oxygen barrier ability. However, PLA has some drawbacks, including brittle, high glass transition temperature (Tg), and low degradation and crystallization rates. Therefore, modification is needed with the addition of nucleating agents and plasticizers to overcome these limitations of PLA. This research aims to study the effect of plasticizers and microfibril cellulose of oil palm frond (OPF) on thermal stability and to review the crystallization kinetics of PLA biocomposites. Polyethylene glycol and triacetin were used as plasticizers. Thermal analysis was performed using Thermal Gravimetry analysis (TGA) and Differential Scanning Calorimetry (DSC). The crystallization kinetics study was analyzed using a modified Avrami model under non-isothermal conditions. PLAP4000 has better thermal stability than PLAP200 and PLAG with Tonset and Tmax values reaching 349.17°C and 374.68°C, respectively, which are close to pure PLA. All types of plasticizers influenced decreasing the Tg value in the range of 27–42%, whereas OPF microfiber addition contributes to a Tg reduction of 37-55 %. Crystallization kinetic study was informed for heterogeneous and simultaneous nucleation mechanisms with an n value range of about 2-3 for PLAP4000 and PLAOP4000. The crystallization rate was multiplied 4-9-fold for PLAOP200 and 2-3-fold for PLAOP4000.


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