A cooling and two-step depressurization foaming approach for the preparation of modified HDPE foam with complex cellular structure

Polymer foam with complex cellular structure (CCS) possessing both large cell and small cell simultaneously has lower density as well as better mechanical and thermal properties than those with mono-porous cell structure, which could be applied in the fields of packaging and construction materials. In this article, organic montmorillonite (OMMT) was introduced into chain-extended poly(butylene succinate) (CPBS) through melt blending method. CCS in the resultant CPBS samples were generated in a stainless steel autoclave using supercritical CO 2 as physical blowing agent by a cooling and two-step depressurization method. The crystallization temperature and crystallinity of CPBS increased by 4 C and 2% respectively, due to the introduction of OMMT. Exfoliated structure of OMMT and some fish scale-like OMMT were observed in the CPBS/OMMT nanocomposites. The optimum range of the first depressurization between 1 and 7 MPa for fabricating the CCS in the CPBS foams with different contents of OMMT was obtained.

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Cellular morphology evolution of chain extended poly(butylene succinate)/organic montmorillonite nanocomposite foam

Zhou

Jia

Ding

et al. 2018

“…With the increase in PE‐ g ‐GMA content, the χ c of various PBS samples kept almost unchanged (Table ), which should be ascribed to two aspects. On the one hand, the branching points in PBS/PE‐ g ‐GMA samples could be acted as the heterogeneous nucleation sites, which could promote PBS crystallization nucleation . On the other hand, the movement of molecular chains of various PBS samples into the crystal lattice was restricted by the existence of branching and/or micro crosslinking structures in PBS, which was adverse to its crystallization growth …”

Section: Resultsmentioning

confidence: 99%

“…Then the insoluble parts were dried at 80 °C for 6 h to remove the residual chloroform. According to the following equation, the gel fraction of various PBS samples was calculated and each sample was measured for three times:

Gel fraction = \frac{W_{0}}{W_{g}} \times 100 %

where W g and W 0 represented the weights of the initial PBS sample and dried insoluble part of sample, respectively.…”

Section: Methodsmentioning

confidence: 99%

Simple and feasible strategy to fabricate microcellular poly(butylene succinate) foams by chain extension and isothermal crystallization induction

Yin

Zhou

et al. 2019

Self Cite

In this article, a facile and efficient isothermal crystallization induction method was proposed to fabricate microcellular poly(butylene succinate) (PBS) foams with supercritical CO2. The good regularity of PE chain segments and high reactive epoxy groups in ethylene‐glycidyl methacrylate copolymer (PE‐g‐GMA) serving as a chain extender were employed to improve the crystallization behaviors, viscoelasticity, and foaming behaviors of PBS through chain extension reaction. The effect of PE‐g‐GMA content on the thermal properties, rheological performances, and cellular morphology of various PBS samples was investigated systematically. When the PE‐g‐GMA content switched from 7.5 to 10 wt %, an interesting transition from fine cells to microcells was observed in PBS/PE‐g‐GMA foams. Microcellular PBS foam modified by 10 wt % PE‐g‐GMA was successfully prepared at the foaming temperature of 87 °C and the induction time of 7 min, in which its cell size and cell density could reach 6.63 ± 1.93 μm and 3.75 × 109 cells cm−3, respectively. The formation of abundant but tiny spherocrystals in chain extended PBS samples made a considerable contribution for preparing microcellular PBS foams. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48850.

Fabricating bimodal microcellular structure in polystyrene/carbon nanotube/glass‐fiber hybrid nanocomposite foam by microwave‐assisted heating: A proof‐of‐concept study

Shahbazi

Aghvami‐Panah

Panahi‐Sarmad

et al. 2022

In the current study, polystyrene/carbon nanotubes/glass fiber (PS/CNT/GF) hybrid foam with a bimodal cellular-structure has been fabricated via microwave heating as a novel energy source. Microwave-assisted (MA) samples not only demonstrated the lowest density as compared to traditional methods but also represented superior compressive mechanical properties. Since the bimodal morphology has not been seen so far, the role of selective microwave heating has been thoroughly investigated from the microstructural point of view. Accordingly, the amount of receiving microwave radiations to heat up the system is controllable via the CNTs (as nucleating agents and absorbers) as well as radiation time. Moreover, 1-15 wt% fibers were incorporated to enhance mechanical performance, which led to turning uniform cellular structure to the bimodal pattern, and its cell morphological was studied thereafter. Electrical conductivity and dielectric permittivity properties have not been deprived of bimodality benefits which have been rigorously proven.