Evolution of double crystal melting peak in polypropylene foam assisted by β-nucleating agent and supercritical CO2

2017 ◽  
Vol 135 (12) ◽  
pp. 46007 ◽  
Author(s):  
Kesong Yu ◽  
Hanchuan Jiang ◽  
Hongfu Zhou ◽  
Jianguo Mi ◽  
Yadong He ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Nucleating Agent ◽  
Melting Peak ◽  
Double Crystal ◽  
Crystal Melting ◽  
Polypropylene Foam

Manufacturing of High-Performance Nano/Microcellular Expanded PLA Bead Foams

2015 ◽  
Author(s):  
Mohammadreza Nofar ◽  
Chul B. Park
Keyword(s):  
High Performance ◽  
Expansion Ratio ◽  
The Other ◽  
Melting Peak ◽  
High Melting ◽  
Double Crystal ◽  
Peak Structure ◽  
Cell Nucleation ◽  
Crystal Melting ◽  
Foaming Technology

In this study, expanded polylactide (EPLA) bead foams were produced with cellular morphology ranging from nanocellular to microcellular. This was achieved by using bead foaming technology while a double crystal melting peak structure was generated. The high melting peak crystals generated during the gas saturation played an important role on controlling the cell size and expansion ratio of the foamed beads. As the amount of high melting peak crystals increased, the cell sizes were reduced to around 350 nm while the expansion ratio was around 3-fold. In other words, the induced perfected crystals significantly promoted the heterogeneous cell nucleation while hindering the cell growth. On the other hand, with the reduced amount of these perfected crystals, the cell sizes were increased to around 15 μm and the expansion ratio of the foamed beads increased to 30-fold.

Double Crystal Melting Peak Generation for Expanded Polypropylene Bead Foam Manufacturing

2013 ◽  
Vol 52 (6) ◽  
pp. 2297-2303 ◽  
Author(s):  
Mohammadreza Nofar ◽  
Yanting Guo ◽  
Chul B. Park
Keyword(s):  
Melting Peak ◽  
Double Crystal ◽  
Crystal Melting

Development of polylactide bead foams with double crystal melting peaks

Polymer ◽  
2015 ◽  
Vol 69 ◽  
pp. 83-94 ◽  
Author(s):  
Mohammadreza Nofar ◽  
Aboutaleb Ameli ◽  
Chul B. Park
Keyword(s):  
Double Crystal ◽  
Crystal Melting

Dual role of PDMS on improving supercritical CO2 foaming of polypropylene: CO2-philic additive and crystallization nucleating agent

2020 ◽  
Vol 163 ◽  
pp. 104888
Author(s):  
Wei Qiang ◽  
Ling Zhao ◽  
Xiulu Gao ◽  
Tao Liu ◽  
Zhen Liu ◽  
...  
Keyword(s):  
Supercritical Co2 ◽  
Nucleating Agent ◽  
Dual Role

scholarly journals A new promising nucleating agent for polymer foaming: effects of hollow molecular-sieve particles on polypropylene supercritical CO2 microcellular foaming

RSC Advances ◽  
2018 ◽  
Vol 8 (36) ◽  
pp. 20061-20067 ◽  
Author(s):  
Chenguang Yang ◽  
Mouhua Wang ◽  
Zhe Xing ◽  
Quan Zhao ◽  
Minglei Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Sieve ◽  
Supercritical Co2 ◽  
Nucleating Agent ◽  
Microcellular Foaming ◽  
Polymer Foaming

Hollow molecular-sieve particles were applied as a new nucleating agent in preparing PP foam with outstanding mechanical properties by using scCO2.

scholarly journals Improving the Supercritical CO2 Foaming of Polypropylene by the Addition of Fluoroelastomer as a Nucleation Agent

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 226 ◽  
Author(s):  
Chenguang Yang ◽  
Quan Zhao ◽  
Zhe Xing ◽  
Wenli Zhang ◽  
Maojiang Zhang ◽  
...  
Keyword(s):  
Cell Size ◽  
Supercritical Co2 ◽  
Deep Understanding ◽  
Local Strain ◽  
Nucleating Agent ◽  
Phase System ◽  
Nucleation Agent ◽  
Cell Size Distribution ◽  
Multiple Phase ◽  
Foaming Behavior

In this study, a small amount of fluoroelastomer (FKM) was used as a nucleating agent to prepare well-defined microporous PP foam by supercritical CO2. It was observed that solid FKM was present as the nanoscale independent phase in PP matrix and the FKM could induce a mass of CO2 aggregation, which significantly enhanced the diffusion rate of CO2 in PP. The resultant PP/FKM foams exhibited much smaller cell size (~24 μm), and more than 16 times cell density (3.2 × 108 cells/cm3) as well as a much more uniform cell size distribution. PP/FKM foams possessed major concurrent enhancement in their tensile stress and compressive stress compared to neat PP foam. We believe that the added FKM played a key role in enhancing the heterogeneous nucleation, combined with the change of local strain in the multiple-phase system, which was responsible for the considerably improved cell morphology of PP foaming. This work provides a deep understanding of the scCO2 foaming behavior of PP in the presence of FKM.

scholarly journals Insight into the Role of a Isophthalic Dihydrazide Derivative Containing Piperonylic Acid in Poly(L-lactide) Nucleation: Thermal Performances and Mechanical Properties

2020 ◽  
Vol 57 (3) ◽  
pp. 28-40
Author(s):  
Hao Huang ◽  
Yan-Hua Zhang ◽  
Li-Sha Zhao ◽  
Guang-Ming Luo ◽  
Yan-Hua Cai
Keyword(s):  
Mechanical Properties ◽  
Nucleating Agent ◽  
Melting Behavior ◽  
Decomposition Temperature ◽  
Melting Peak ◽  
Melt Crystallization ◽  
Scanning Calorimetry ◽  
Melt Temperature ◽  
Onset Crystallization Temperature ◽  
Tensile Tester

This work was aimed at synthesizing the N, N -isophthalic bis(piperonylic acid) dihydrazide (PAID) to be as a new crystallization accelerator for poly(L-lactide) (PLLA), and a detailed investigations of the non-isothermal crystallization, melting behavior, thermal decomposition behavior and mechanical properties of PLLA nucleated by PAID were performed applying differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and electronic tensile tester. The melt-crystallization proved that the PAID could act as a heterogeneous nucleating agent to significantly promote the crystallization in cooling, even the crystallization was still able to be accelerated upon the fast cooling at 50 oC/min. The final melt temperature was another crucial factor for PLLA�s melt crystallization, and when the final melt temperature was 170 oC, the onset crystallization temperature and melt-crystallization enthalpy was almost up to 150 oC and 56.8 J/g upon cooling of 1 oC/min, respectively. Furthermore, the chemical nucleation was proposed to be the nucleation mechanism of PAID for PLLA via the preliminary theoretical calculation. For the cold-crystallization, the addition of PAID exhibited an inhibition for the crystallization of PLLA, but the total crystallization process depended on the heating rate and PAID concentration. The single melting peak after cooling of 1 oC/min indicated that the crystallization had been thoroughly completed in cooling. Additionally, the single melting peak with different locations after full crystallization resulted from the different crystallization temperatures. A comparison in the onset decomposition temperature implied that the presence of PAID only slightly decreased the thermal stability of PLLA. The mechanical testing showed that, in contrast with the elongation at break, the existence of PAID enhanced the tensile strength of PLLA.

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