Crystallization and properties of nucleated poly(l-lactic acid): Effect of cyclopentanecarboxylic acid derivative as a new nucleating agent

2021 ◽  
pp. 089270572110019
Author(s):  
Lisha Zhao ◽  
Xuhua Liu ◽  
Yanhua Cai ◽  
Wei Chen
Keyword(s):  
Lactic Acid ◽  
Cooling Rate ◽  
Melting Temperature ◽  
Tensile Modulus ◽  
Nucleating Agent ◽  
Orbital Energy ◽  
Melt Crystallization ◽  
Promoting Effect ◽  
Crystallization Peak ◽  
Lower Temperature

In this study, the potential effects of N, N’-dodecanedioic bis(cyclopentanecarboxylic acid) dihydrazide (BCADD) as a new additive in poly(L-lactic acid) (PLLA) was estimated. The comparative study on the melt-crystallization showed that the BCADD as heterogeneous nuclei facilitated crystallization of PLLA in cooling, which indicated by the obvious crystallization exotherms and sharp melt-crystallization peak. Unfortunately, with increasing of BCADD from 0.5 wt% to 3 wt%, it is unexpected that the melt-crystallization peak of the BCADD-nucleated PLLA shifted toward the lower temperature and became flatter, evidencing the importance of BCADD loading for PLLA’s crystallization. Additionally, the cooling rate and the final melting temperature were also proved to be important influence factors during PLLA’s melt-crystallization process, but in contrast with the effect of the final melting temperature on the melt-crystallization, a higher cooling rate could more seriously weaken crystallization ability of the BCADD-nucleated PLLA. The chemical nucleation mechanism was proposed to explain the promoting effect of BCADD on the crystallization of PLLA via the analysis of frontier orbital energy. The melting behaviors after crystallization further confirmed the crystallization accelerating role of BCADD, and the melting behaviors were affected by the heating rate, crystallization temperature and BCADD loading. Although the onset thermal decomposition of the BCADD-nucleated PLLA occurred at lower temperature comparing with the pure PLLA, the intermolecular interaction of PLLA with BCADD attempted to prevent the decrease of thermal stability. Overall, the addition of BCADD resulted in the complicated effect on the tensile modulus and tensile strength of PLLA, but the elongation at break continuously decreased when increasing BCADD loading.

scholarly journals The Crystallization, Melting Behavior, and Thermal Stability of Poly(L-lactic acid) Induced byN,N,N′-Tris(benzoyl) Trimesic Acid Hydrazide as an Organic Nucleating Agent

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yan-Hua Cai ◽  
Yan-Hua Zhang
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Cooling Rate ◽  
Acid Hydrazide ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Crystallization Peak ◽  
Trimesic Acid ◽  
Neat Plla ◽  
Thermal Stability Of

N,N,N′-Tris(benzoyl) trimesic acid hydrazide (TTAD), as a novel nucleating agent of poly(L-lactic acid) (PLLA), was synthesized and characterized by FT-IR and1H NMR. The crystallization, melting behavior, and thermal stability of PLLA induced by TTAD were investigated through DSC, TGA, depolarized-light intensity measurement, and so forth. The crystallization behavior indicated that the presence of TTAD accelerated the overall PLLA crystallization. Compared to neat PLLA, the crystallization onset temperature of PLLA/1%TTAD increased from 101.36°C to 125.26°C, the melt-crystallization peak temperature increased from 94.49°C to 117.56°C, crystallization enthalpy increased from 0.1023 J·g−1to 33.44 J·g−1at a cooling rate of 1°C/min from melt, and the crystallization half-time of PLLA/TTAD decreased from 2997.2 s to 108.9 s at 110°C. Moreover, the nonisothermal crystallization measurements also indicated that the crystallization peak became wider and shifted to a lower temperature with increasing cooling rate. With the presence of TTAD, the melting behavior of PLLA was affected significantly, and a double-melting peak occurred due to melting-recrystallization. Thermal stability research showed that there existed one degradation stage of PLLA and PLLA/TTAD samples, and the thermal degradation temperature of PLLA/TTAD decreased compared to neat PLLA.

A 1H-Benzotriazole Derivative Nucleated Poly(L-lactic acid): Thermal Behavior and Physical Properties

2020 ◽  
Vol 42 (3) ◽  
pp. 383-383
Author(s):  
Li Sha Zhao and Yan Hua Cai Li Sha Zhao and Yan Hua Cai
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Melting Process ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Cold Crystallization ◽  
Melt Crystallization ◽  
Nucleation Effect ◽  
Lower Temperature ◽  
Thermal Stability Of

In this study, a 1H-benzotriazole derivative, N, Nand#39;-bis(1H-benzotriazole) succinic acid acethydrazide (SABHA), was synthesized to nucleate Poly(L-lactic acid) (PLLA). A series of comparative studies on the melt-crystallization, the cold-crystallization, the melting behavior, the thermal stability, as well as the fluidity between the pure PLLA and PLLA/SABHA were performed. The melt-crystallization behavior revealed that the SABHA as a heterogeneous nucleating agent could significantly facilitate the crystallization of PLLA, and a larger amount of SABHA concentration exhibited the better nucleation effect. However, for the cold-crystallization process, the crystallization peak shifted toward the lower temperature with increasing of SABHA concentration. The melting behavior after crystallization at different crystallization temperatures showed that the melting process of PLLA/SABHA samples depended on the crystallization temperature, and the appearance of the double melting peaks was attributed to the melt-recrystallization. The thermal decomposition profile of PLLA was not affected by SABHA, but the addition of SABHA reduced the thermal stability of PLLA. Fortunately, the presence of SABHA improved the fluidity of PLLA, and the effect of SABHA concentration on the fluidity was positive.

scholarly journals Physical Properties of Biodegradable Poly(L-lactide) Induced by N, N -Bis(Benzoyl) 1, 3-Cyclohexanedicarboxylic Acid Dihydrazide as Crystallinity Additive

2021 ◽  
Vol 58 (2) ◽  
pp. 48-59
Author(s):  
Li-Sha Zhao ◽  
Ting Deng ◽  
Jun Qiao ◽  
Yan-Hua Cai
Keyword(s):  
Cooling Rate ◽  
Heating Rate ◽  
Melting Temperature ◽  
Crystallization Process ◽  
Melting Behavior ◽  
Cold Crystallization ◽  
Light Transmittance ◽  
Melt Crystallization ◽  
Crystallization Peak ◽  
Crystallization Ability

This work is aimed at synthesizing an organic compound N, N -bis(benzoyl) 1,3-cyclohexane-dicarboxylic acid dihydrazide (CABH) to focus on its effect on the non-isothermal crystallization of poly(L-lactide) (PLLA), meanwhile the melting behavior, thermal decomposition process and optical property of PLLA/CABH samples in different CABH concentrations were also investigated. It was found that CABH acted as efficient heterogeneous nucleating agent for inducing PLLA�s crystallization through comparative analysis of melt-crystallization process of the virgin PLLA with PLLA/CABH samples, and a high amount of CABH played a much more significant role in promoting PLLA�s crystallization. Additionally, the melt-crystallization processes also showed that both the cooling rate and the final melting temperature affected the crystallization behavior of PLLA, an increase of cooling rate could weaken the crystallization ability of PLLA/CABH samples, and the final melting temperature of 180�C made PLLA/CABH exhibit the best crystallization ability. For the cold-crystallization process, the cold-crystallization peak became flatter and shifted toward the lower temperature with increasing of CABH concentration, but an increase of heating rate could prevent the cold-crystallization peak from moving to low temperature because of the thermal inertia. The melting behaviors of PLLA/CABH depended on the previous crystallization and heating rate in heating, and the difference in melting behavior of PLLA/CABH samples effectively reflected the nucleation role of CABH, as well as the double melting peaks behavior of PLLA/CABH was thought to due to the melting-recrystallization. The introduction of CABH led to a drop in light transmittance, moreover, this negative effect were more obvious with an increase of CABH loading. In contrast, the fluidity of PLLA was significantly enhanced due to the existence of CABH.

scholarly journals Insight on the effect of a piperonylic acid derivative on the crystallization process, melting behavior, thermal stability, optical and mechanical properties of poly(l-lactic acid)

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 203-213
Author(s):  
Li-Sha Zhao ◽  
Yan-Hua Cai
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Lactic Acid ◽  
Cooling Rate ◽  
Acid Derivative ◽  
Melting Process ◽  
Nucleating Agent ◽  
Cold Crystallization ◽  
Melt Crystallization ◽  
Optical And Mechanical Properties

AbstractA new piperonylic acid derivative (BPASD) was synthesized and evaluated as an organic nucleating agent for poly(l-lactic acid) (PLLA) via melt-crystallization; the other behaviors including cold-crystallization, melting process after crystallization, thermal stability in air atmosphere, and optical and mechanical properties of PLLA/BPASD samples were also investigated. The results of the melt-crystallization investigation showed that, in comparison to virgin PLLA, the BPASD could induce PLLA to crystallize in higher temperature region or at a faster cooling rate, suggesting that the BPASD as a heterogeneous nucleating agent could promote the crystallization of PLLA, but the melt-crystallization depended on the cooling rate, BPASD concentration, and the final melting temperature. With increasing of BPASD concentration, a shift to the lower temperature of cold-crystallization peak and decrease of crystallization enthalpy indicated that BPASD had an inhibition for the cold-crystallization of PLLA to some extent. The heating rate, crystallization temperature, the BPASD, and its concentration were critical factors to the melting process, and double-melting peaks appeared in heating were assigned to melting–recrystallization. Thermal decomposition behavior revealed that the addition of BPASD reduced the thermal stability of PLLA, but the interaction of PLLA and BPASD could prevent the decrease of the onset decomposition temperature. Further, the BPASD also decreased the light transmittance and elongation at the break of PLLA, but the tensile modulus and tensile strength of PLLA were enhanced.

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 Comparison of the efficiency of the most effective heterogeneous nucleating agents for Poly(lactic acid)

2021 ◽  
Author(s):  
Tatyana Ageyeva ◽  
József Gábor Kovács ◽  
Tamás Tábi
Keyword(s):  
Lactic Acid ◽  
Tensile Modulus ◽  
Charpy Impact ◽  
Nucleating Agent ◽  
Poly Lactic Acid ◽  
Nucleating Agents ◽  
Scanning Calorimetry ◽  
Injection Molded ◽  
Heat Deflection Temperature ◽  
Charpy Impact Strength

AbstractWe selected the thirteen most effective nucleating agents for Poly(lactic acid) (PLA) from the literature, and synthesized and compounded them with two different PLA grades: 3001D (1.4% D-lactide content) and 3100HP (0.5% D-lactide content, considered PLLA). We determined the crystallinity and crystallization of PLA with different nucleating agents in identical conditions (same nucleating agent content, same cooling rate) with the help of differential scanning calorimetry. We compared the efficiency of each nucleating agent and found that for both PLA grades, Zinc PhenylPhosphonate was the most effective. However, even when nucleated PLA was injection molded into a cold mold (25 °C), it still could not fully crystallize during cooling and the heat deflection temperature did not increase significantly. The maximum achieved crystallinity, in this case, was between 32.4 and 35.7%. On the contrary, when a 90 °C “hot mold” and in-mold crystallization together were applied, the specimens achieved full crystallization during the injection molding cycle (crystallinity was between 44.5 and 50.0%), and the heat deflection temperature increased to an average of 88.8 °C. We also examined the mechanical properties of the nucleated PLA and found that the usage of nucleating agents together with a hot mold improved tensile strength, tensile modulus, and Charpy impact strength but decreased elongation at break.

scholarly journals Effect of Cyanuric Acid as an Efficient Nucleating Agent on the Crystallization of Novel Biodegradable Branched Poly(Ethylene Succinate)

Macromol ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 112-120
Author(s):  
Kangjing Zhang ◽  
Zhaobin Qiu
Keyword(s):  
Cyanuric Acid ◽  
Crystallization Rate ◽  
Nucleating Agent ◽  
Crystallization Mechanism ◽  
Nucleation Density ◽  
Half Time ◽  
Melt Crystallization ◽  
Casting Method ◽  
Crystallization Peak ◽  
Poly Ethylene

Novel biodegradable branched poly(ethylene succinate) (b-PES) composites, i.e., nucleated b-PES samples, were prepared by incorporating low loadings of cyanuric acid (CA) through a solution and casting method to enhance the crystallization rate. As an efficient nucleating agent, CA could remarkably increase the nonisothermal melt crystallization peak temperature, shorten the crystallization half-time, accelerate the overall isothermal melt crystallization, and enhance the nucleation density of b-PES spherulites in the composites. Despite the addition of CA, the crystallization mechanism and crystal structure of b-PES remained unchanged. A possible epitaxial crystallization mechanism may account for the nucleation of b-PES crystals induced by CA.

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.

scholarly journals Poly (L-lactic acid) Modified by N, N -bis(Stearic acid)-1,4-Dicarboxybenzene Dihydrazide: Studies of Crystallization, Melting Behavior and Thermal Decomposition

2022 ◽  
Vol 58 (4) ◽  
pp. 73-83
Author(s):  
Hao Huang ◽  
Shuang-Qing Liu ◽  
Cheng-Pei Li ◽  
Shi-Tianle Luo ◽  
Li-Sha Zhao ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Lactic Acid ◽  
Stearic Acid ◽  
Isothermal Crystallization ◽  
Crystallization Process ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Melt Crystallization ◽  
Thermal Stability Of

In this study, a new organic nucleating agent N, N -bis(stearic acid)-1,4-dicarboxybenzene dihydrazide (PASH) to improve crystallization behavior of poly(L-lactic acid) (PLLA) along with the effect of PASH on melting behavior, thermal stability of PASH-nucleated PLLA was holistically reported. The melt-crystallization process illustrated that PASH as an effective heterogeneous nucleating agent could boost PLLA�s crystallization rate, but increasing PASH concentration and cooling rate conversely inhibited melt-crystallization process of PLLA in this study. With respect to melt-crystallization process, a larger amount of PASH leaded to a shift of cold-crystallization peak to lower temperature level. Isothermal crystallization revealed, in comparison to pure PLLA, that the half time of overall crystallization of PLLA/PASH was significantly decreased with PLLA containing 3 wt% PASH having the minimum t1/2= 67.3 s at 105şC. The different melting behaviors of PLLA/PASH under different conditions were attributed to the nucleating effect of PASH within PLLA. In particular, the melting behavior at a heating rate of 10�C/min after isothermal crystallization depended primarily on the crystallization temperature. Whereas, the impact of crystallization time on melting behavior was negligible. Nonetheless, the melting behavior was influenced by the heating rate after non-isothermal crystallization. The thermal stability of PLLA was detrimental with the addition of PASH owing to a typical drop in onset thermal decomposition temperature.

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