Study on the thermal stability of heterogeneous nucleation effect of polypropylene nucleated by different nucleating agents

2001 ◽  
Vol 83 (8) ◽  
pp. 1643-1650 ◽  
Author(s):  
Kancheng Mai ◽  
Kefeng Wang ◽  
Zhiwu Han ◽  
Hanmin Zeng
Keyword(s):  
Thermal Stability ◽  
Heterogeneous Nucleation ◽  
Nucleating Agents ◽  
Nucleation Effect ◽  
Thermal Stability Of

scholarly journals Heterogeneous Nucleation Effect of N, N'-Adipic Bis(4-phenylbutyric Acid) Dihydrazide on Crystallization Process of Poly(L-lactic Acid)

2019 ◽  
Vol 25 (4) ◽  
pp. 446-454
Author(s):  
Yan-Hua CAI ◽  
Li-Sha ZHAO
Keyword(s):  
Thermal Stability ◽  
Lactic Acid ◽  
Heterogeneous Nucleation ◽  
Isothermal Crystallization ◽  
Crystallization Process ◽  
Melting Behavior ◽  
Light Transmittance ◽  
Crystallization Peak ◽  
Nucleation Effect ◽  
Phenylbutyric Acid

Enhancing crystallization ability is a fundamental challenges in Poly(L-lactic acid) (PLLA) industry, therefore, the goal of this work was to synthesis a new organic nucleating agent N, N'-adipic bis(4-phenylbutyric acid) dihydrazide (APAD), and investigate its effect on non-isothermal crystallization, isothermal crystallization, melting behavior, thermal stability, and optical property of PLLA. Non-isothermal melt crystallization results showed that APAD acted as more effective nucleating and accelerating agent for the crystallization of PLLA, as a result, upon cooling at 1 °C/min, PLLA/0.5 %APAD had the highest onset crystallization temperature 136.4 °C and the crystallization peak temperature 132.0 °C, as well as the largest non-isothermal crystallization enthalpy 48.1 J/g. However, with increasing of APAD concentration from 0.5 wt.% to 3 wt.%, the crystallization peak shifted to the lower temperature. In contrast, for the non-isothermal cold crystallization process, the effect of APAD concentration on the crystallization behavior of PLLA was negligible. Additionally, the non-isothermal crystallization process was also depended on the cooling rates and the final melting temperature. In isothermal crystallization section, to compare with the primary PLLA, the crystallization half-time of PLLA/APAD could decrease from 254.3 s to the minimum value 29.4 s, with 0.5 wt.% APAD contents at 125 °C. Melting behavior of PLLA/APAD samples under different conditions further confirmed the heterogeneous nucleation effect of APAD for PLLA, and the appearance of the double melting peaks was attributed to the melting-recrystallization. Finally, the addition of APAD decreased the thermal stability to some extent, although APAD could not change the thermal decomposition profile of PLLA. And a drop of PLLA/APAD samples in light transmittance resulted from the double influence of the enhancement of crystallization and the opaqueness of APAD.

scholarly journals Polypropylene Blend with Polyphenols through Dynamic Vulcanization: Mechanical, Rheological, Crystalline, Thermal, and UV Protective Property

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1108 ◽  
Author(s):  
Jingjing Liao ◽  
Nicolas Brosse ◽  
Antonio Pizzi ◽  
Sandrine Hoppe ◽  
Xuedong Xi ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Thermal Stability ◽  
Protective Property ◽  
Nucleating Agents ◽  
Small Particle Size ◽  
Dynamic Vulcanization ◽  
Carbonyl Index ◽  
Protection Property ◽  
Protective Performance ◽  
Thermal Stability Of

Tannin and lignin were blended with polypropylene (PP) through dynamic vulcanization technique. Their influence of mechanical property, crystallinity, thermal stability, as well as ultraviolet (UV) protection property on the PP matrix was investigated and compared with native tannin and lignin. According to our experimental results, tannin and lignin undergo dynamic vulcanization and were more compatible with the PP matrix. Besides, tannin and vulcanized tannin can perform as nucleating agents of PP because of their relatively small particle size. Moreover, vulcanized tannin/lignin have a better performance on the thermal stability of PP compared with native tannin/lignin, especially PP/vulcanized lignin blend. Furthermore, vulcanized tannin/lignin present better UV protective performance, concluded from fewer changes on surface morphology, carbonyl index, crystallinity, viscosity, and tensile property.

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 Sustainable nanocomposite films based on SiO2 and biodegradable poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) for food packaging

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 072-081
Author(s):  
Yujuan Qiu ◽  
Jirui Fu ◽  
Binqing Sun ◽  
Xiaojun Ma
Keyword(s):  
Thermal Stability ◽  
Migration Rate ◽  
Food Packaging ◽  
Oxygen Permeability ◽  
Barrier Properties ◽  
Nanocomposite Films ◽  
Solvent Casting ◽  
Nucleating Agents ◽  
Biodegradable Poly ◽  
Thermal Stability Of

Abstract Sustainable nanocomposites with transparent, biodegradable, and enhanced mechanical and barrier properties were prepared by the incorporation of SiO2 into poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) films and subsequent solvent casting. The crystallinity of composites could be increased by 67% with appropriate contents of SiO2, which proved that SiO2 were effective nucleating agents for PHBH. And it was worth mentioning that the contributions of SiO2 to the crystallization and thermal stability of composites are proved effectively by Avrami relationship and Horowitz and Metzger method. More importantly, compared with PHBH, it had not only an enhancement about 40% and 60% on the tensile strength and elastic modulus, respectively, but also half the reduction of the moisture and oxygen permeability which were much higher than the values of conventional plastics. The above, in conjunction with the low migration rate measured in food substitutes, illustrated unambiguously that the nanocomposites might be suitable for potential application in food packaging.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Microstructure studies of tungsten silicide schottky contacts on Gaas

1987 ◽  
Vol 45 ◽  
pp. 328-329
Author(s):  
Yih-Cheng Shih ◽  
E. L. Wilkie
Keyword(s):  
Thermal Stability ◽  
Field Effect Transistors ◽  
Schottky Contact ◽  
Schottky Contacts ◽  
Excellent Thermal Stability ◽  
Barrier Heights ◽  
Gaas Substrates ◽  
Film Adhesion ◽  
Threshold Voltages ◽  
Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

Thermal stability of Al-Cu-Fe icosahedral alloys

1991 ◽  
Vol 1 (12) ◽  
pp. 1823-1836 ◽  
Author(s):  
M. Bessière ◽  
A. Quivy ◽  
S. Lefebvre ◽  
J. Devaud-Rzepski ◽  
Y. Calvayrac
Keyword(s):  
Thermal Stability ◽  
Thermal Stability Of

Practical criteria for the thermal stability of a unidimensional superconductor

1994 ◽  
Vol 4 (4) ◽  
pp. 653-657
Author(s):  
B. Bonzi ◽  
M. El Khomssi ◽  
H. Lanchon-Ducauquis
Keyword(s):  
Thermal Stability ◽  
Thermal Stability Of

Time and thermal stability of magnetic properties of amorphous Fe80TM3B17 alloys

1998 ◽  
Vol 08 (PR2) ◽  
pp. Pr2-63-Pr2-66 ◽  
Author(s):  
R. Varga ◽  
P. Vojtaník ◽  
A. Lovas
Keyword(s):  
Thermal Stability ◽  
Magnetic Properties ◽  
Thermal Stability Of
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