Isothermal and Non-Isothermal Crystallization Behavior of Poly(L-Lactic Acid) with Nucleating Agents

2011 ◽  
Vol 335-336 ◽  
pp. 1299-1302 ◽  
Author(s):  
Xin Qian ◽  
Mi Zhou ◽  
Dong Xu ◽  
Shu Jun Xu ◽  
Yang Fu Jin
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Peak Temperature ◽  
Crystallization Time ◽  
Nucleating Agents ◽  
Scanning Calorimetry ◽  
Crystallization Peak ◽  
Half Crystallization Time

The effects of Amide type nucleating agents SX , talc and nucleating agents SX combination with talc on crystallization behavior of poly (L-lactic acid）(PLLA) were analyzed by means of Differential scanning calorimetry (DSC)．The results of non-isothermal crystallization showed that SX is an efficient nucleating agent. The crystallization peak temperature and degree of crystallization of PLLA sample with 0.6 wt% SX are both higher than that of PLLA sample with 4 wt% Talc，which proved that the nucleating ability of SX is stronger．Nucleating agent SX and talc combination has obvious coordination effects, the sample of PLLA/0.2 wt % SX + 4 wt % talc has the minimal crystallization undercooling temperature, the highest crystallization peak temperature and crystallinity. Isothermal crystallization kinetics of PLA showed that when the four nucleating agents added in are all with the Avrami exponent n between 2.1-2.5, crystallization tended to be heterogeneous nucleation. When the nucleating agents added in are 0.6 wt%, the crystallization time is greatly decreased to 0.75min. Meanwhile, the PLLA crystallinity could be significantly increased by adding SX nucleating agents; besides, with the decrease of the isothermal crystallization temperature, the half crystallization time of the PLLA/0.6 wt% SX sample was decreased.

scholarly journals Effect of different nucleating agent on crystallization kinetics and morphology of polypropylene

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Yanjie An ◽  
Sihan Wang ◽  
Rui Li ◽  
Dezhu Shi ◽  
Yuxin Gao ◽  
...  
Keyword(s):  
Crystallization Kinetics ◽  
Crystallization Behavior ◽  
Polarized Light ◽  
Nucleating Agent ◽  
Crystallization Time ◽  
Nucleating Agents ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Half Crystallization Time

AbstractThe effects of phosphate nucleating agent (NA), carboxylate nucleating agent (MD), rosin type nucleating agent (WA) and sorbitol nucleating agent (NX) on crystallization behavior of isotactic polypropylene were investigated by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and polarized light microscopy (PLM). The results showed that different structure nucleating agents significantly affected the crystallization kinetics, rate and temperature of polypropylene. Among them, half crystallization time of NX nucleating agent was the shortest, which was 53.4 seconds, and the crystallization temperature was the highest, reaching 129.8°C.

Isothermal Crystallization Behavior of Poly (L-lactic Acid)/ Surface-Grafted Silica Nanocomposites

2012 ◽  
Vol 268-270 ◽  
pp. 37-40 ◽  
Author(s):  
Yan Hua Cai
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Melt Blending ◽  
Scanning Calorimetry ◽  
Silica Nanocomposites ◽  
Induction Periods ◽  
Sio2 Nanocomposites ◽  
Different Content

The Poly(L-lactic acid)(PLLA)/surface-grafting silica(g-SiO2) nanocomposites were prepared by melt blending. The isothermal crystallization behavior of PLLA/g-SiO2 nanocomposites with different content of g-SiO2 was investigated by optical depolarizer. In isothermal crystallization from melt, the induction periods and half times for overall PLLA crystallization (95°C Tc 120°C) were affected by the crystallization temperature and the content of g-SiO2 in nanocomposites. The results showed that g-SiO2 as a kind of heterogeneous nucleating agent can reduce induction periods and half times for overall PLLA crystallization. The thermal properties of PLLA/g-SiO2 samples were also investigated by differential scanning calorimetry (DSC), The results showed that the crystalline degree of PLLA was improved as the presence of g-SiO2.

Thermal behavior of modified poly(L-lactic acid): effect of aromatic multiamide derivative based on 1H-benzotriazole

e-Polymers ◽  
2016 ◽  
Vol 16 (4) ◽  
pp. 303-311 ◽  
Author(s):  
Yan-Hua Cai ◽  
Li-Sha Zhao
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Onset Crystallization Temperature

AbstractThe goal of this work was to synthesis a novel aromatic multiamide derivative based on 1H-benzotriazole (PB) as an organic nucleating agent for poly(L-lactic acid) (PLLA), and investigate the effect of PB on the non-isothermal crystallization, melting behavior and thermal decomposition of PLLA. Here, PB was firstly synthesized through 1H-benzotriazole aceto-hydrazide and terephthaloyl chloride, then PB-nucleated PLLA was fabricated via melt-blending technology at various PB concentration from 0.5 wt% to 3 wt%. Finally, the thermal performances were evaluated through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The high thermal decomposition temperature of PB indicated that PB possessed possibility as a nucleating agent for PLLA, and the non-isothermal crystallization behavior confirmed the crystallization accelerating effectiveness of PB for PLLA. Upon optimum concentration of 2 wt%, the onset crystallization temperature, the crystallization peak temperature and the non-isothermal crystallization enthalpy increased from 101.4°C, 94.5°C and 0.1 J·g-1 to 121.3°C, 115.8°C and 35.1 J·g-1, respectively. In addition, the non-isothermal crystallization behavior was also affected by the cooling rate and the final melting temperature. The melting behavior further evidenced the advanced nucleating ability of PB, and the competitive relationship between PB and the heating rate, the nuclear rate and crystal growth rate. Thermal stability measurement showed that PB with a concentration of 1 wt%–2 wt% could slightly improve the thermal stability of PLLA.

Isothermal Crystallization Behavior and Kinetics of Poly (lactic acid) Filled with a Novel Nucleating Agent

2014 ◽  
Vol 887-888 ◽  
pp. 716-722
Author(s):  
Nai Xu ◽  
Xing Hui Wang ◽  
Li Sha Pan ◽  
Su Juan Pang ◽  
Xuan Chen ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Nucleating Agent ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Nucleation Effect ◽  
Amide Derivatives ◽  
Aromatic Amide ◽  
Kinetics Of

The crystallization behavior and crystalline structure of poly (lactic acid) (PLA) filled with a novel nucleating agent (TMC328), which is a kind of aromatic amide derivatives, were investigated using differential scanning calorimetry (DSC) and wide angle X-ray (XRD). In isothermal crystallization from the melt, the present of TMC328 remarkably affected the isothermal crystalline behaviors of PLA. PLA/0.5% TMC328 sample exhibited very short crystallization half-times at 90-130 °C. Furthermore, the Avrami theory was used to describe the isothermal crystallization kinetics of PLA/TMC328 samples. It is confirmed that TMC328 showed a significant heterogeneous nucleation effect on the crystallization of PLA matrix. Moreover, XRD measurement indicates that TMC328 is a kind of α-form nucleating agent for PLA.

scholarly journals Non-isothermal Crystallization, Thermal Stability, and Mechanical Performance of Poly(L-lactic acid)/Barium Phenylphosphonate Systems

2017 ◽  
Vol 15 (1) ◽  
pp. 248-254 ◽  
Author(s):  
Yan-Hua Cai ◽  
Li-Sha Zhao
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Mechanical Performance ◽  
Nucleating Agent ◽  
Crystal Form ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Crystallization Peak

AbstractThe introduction of a nucleating agent in semi-crystalline polymers is a frequently utilized way to improve the crystallization performance, and the use of a nucleating agent has a very great effect on the performance of the polymer in other areas including thermal stability and mechanical properties. In this investigation, barium phenylphosphonate (BaP) was prepared as a crystallization accelerator for Poly(L-lactic acid) (PLLA), and the non-isothermal crystallization behavior, thermal stability, and mechanical properties of PLLA modified by BaP were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and electronic tensile testing. Non-isothermal crystallization analysis showed that the BaP could significantly accelerate the crystallization of PLLA, and the non-isothermal crystallization peak shifted to a higher temperature with increasing concentration of BaP, however, the corresponding crystallization peak became wider. XRD results after non-isothermal crystallization confirmed the non-isothermal crystallization DSC results. Additionally, the addition of BaP did not change the crystal form of PLLA. A comparative study on thermal stability indicated that BaP decreased the onset decomposition temperature of PLLA, resulting from the formation of more tiny and imperfect crystals. Whereas the influence of BaP on the thermal decomposition profile of PLLA was negligible. In terms of mechanical properties, the tensile strength and elastic modulus of PLLA/BaP increased compared to the virgin PLLA, unfortunately, the elongation at break decreased.

Non-isothermal crystallization behavior of polypropylene/zinc oxide composites

2016 ◽  
Vol 23 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Jianqiang Fang ◽  
Minghua Lang ◽  
Xuchu Ye ◽  
Wei Zhang ◽  
Kongjun Zhu
Keyword(s):  
Activation Energy ◽  
Zinc Oxide ◽  
Isothermal Crystallization ◽  
Crystallization Behavior ◽  
Crystallization Kinetic ◽  
Exothermic Peak ◽  
Crystallization Time ◽  
Scanning Calorimetry ◽  
Relative Crystallinity ◽  
Oxide Composites

AbstractThe non-isothermal crystallization behavior of polypropylene (PP)/zinc oxide composites with various mass ratios was investigated by differential scanning calorimetry. The Jeziorny and Mo models were applied to calculate the non-isothermal crystallization kinetic parameters of the composites. During non-isothermal crystallization, the width of the exothermic peak increased from 7°C to 12°C with increasing cooling rate. The exothermic peak position at 10°C shifted to a lower temperature, and the half crystallization time t1/2 decreased from 2.86 min to 0.51 min. The Friedman model was used to determine the variation of activation energy at each stage of crystallization. The crystallization activation energies obtained varied significantly at each stage of crystallization. The crystallization activation energy of PP was -126.8 kJ/mol at 70% relative crystallinity but reached -232.8 kJ/mol at 10% relative crystallinity.

Crystallization Properties of Nucleated Poly(lactic acid)

2012 ◽  
Vol 549 ◽  
pp. 322-326 ◽  
Author(s):  
Yong Chen ◽  
Qiang Dou
Keyword(s):  
Lactic Acid ◽  
Crystallization Behavior ◽  
Polarized Light ◽  
Nucleating Agent ◽  
Poly Lactic Acid ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Crystallization Properties ◽  
Melting And Crystallization

The effect of a nucleating agent (NT-C) on the crystallization behavior of poly(lactic acid) (PLA) was studied. The melting and crystallization behavior and spherulitic morphology of the nucleated PLA were investigated by means of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarized light microscopy (PLM). It is found that the crystallization temperature and crystallinity increase, the spherulitic size decrease for the nucleated PLA. But the crystal structure of the nucleated PLA is not changed.

Preparation and Isothermal Crystallization Behavior of Poly(lactic acid)/Graphene Nanocomposites

2011 ◽  
Vol 284-286 ◽  
pp. 246-252 ◽  
Author(s):  
Yan Hua Chen ◽  
Xia Yin Yao ◽  
Zhi Juan Pan ◽  
Qun Gu
Keyword(s):  
Lactic Acid ◽  
Isothermal Crystallization ◽  
Graphene Nanosheets ◽  
Nucleating Agent ◽  
Optical Microscope ◽  
Poly Lactic Acid ◽  
Scanning Calorimetry ◽  
Avrami Model ◽  
Graphene Nanocomposites ◽  
Solution Blending

Poly(lactic acid) (PLA)/graphene nanocomposites were prepared by solution blending using chloroform as a mutual solvent. Transmission electron microscopy (TEM) was used to examine the quality of the dispersion of graphene in the PLA matrix. The isothermal crystallization behaviors of PLA and PLA/graphene nanocomposites were investigated by differential scanning calorimetry (DSC). The isothermal crystallization kinetics were analyzed by Avrami model based on the DSC data. The results showed that the well dispersed graphene nanosheets could act as a heterogeneous nucleating agent and lead to an acceleration of crystallization during the PLA isothermal crystallization process. According to the Arrhenius equation, the activation energies were found to be -106.9 and -46.6 kJ/mol for pure PLA and PLA/0.1 wt % graphene nanocomposite, respectively. The crystal morphology were characterized with polarizing optical microscope (POM).

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