Chemical Cross-linking of Polypropylenes Towards New Shape Memory Polymers

2015 ◽  
Vol 36 (8) ◽  
pp. 744-749 ◽  
Author(s):  
Thomas Raidt ◽  
Robin Hoeher ◽  
Frank Katzenberg ◽  
Joerg C. Tiller
2021 ◽  
Author(s):  
Lulu Pan ◽  
Jianfeng Ban ◽  
Tiwen Xu ◽  
Ruiquan Liu ◽  
Shaorong Lu

A new type of sisal-based shape memory polyurethane foam (SMPU-PSF) was prepared by chemical cross-linking of hydroxyl groups on sisal cellulose (PSF) with polycaprolactone and MDI, which used PSF as...


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2330
Author(s):  
Tao Xi Wang ◽  
Hong Mei Chen ◽  
Abhijit Vijay Salvekar ◽  
Junyi Lim ◽  
Yahui Chen ◽  
...  

The shape memory effect (SME) refers to the ability of a material to recover its original shape, but only in the presence of a right stimulus. Most polymers, either thermo-plastic or thermoset, can have the SME, although the actual shape memory performance varies according to the exact material and how the material is processed. Vitrimer, which is between thermoset and thermo-plastic, is featured by the reversible cross-linking. Vitrimer-like shape memory polymers (SMPs) combine the vitrimer-like behavior (associated with dissociative covalent adaptable networks) and SME, and can be utilized to achieve many novel functions that are difficult to be realized by conventional polymers. In the first part of this paper, a commercial polymer is used to demonstrate how to characterize the vitrimer-like behavior based on the heating-responsive SME. In the second part, a series of cases are presented to reveal the potential applications of vitrimer-like SMPs and their composites. It is concluded that the vitrimer-like feature not only enables many new ways in reshaping polymers, but also can bring forward new approaches in manufacturing, such as, rapid 3D printing in solid state on space/air/sea missions.


2021 ◽  
Vol 36 (1) ◽  
pp. 26-34
Author(s):  
Q. Ren ◽  
X. J. Wang ◽  
Y. Q. Zhao ◽  
L. Q. Xu ◽  
H. W. Yu ◽  
...  

Abstract Shape memory polymers (SMPs) are developed by blending and cross-linking polymers which include crystalline domains and cross-linked networks. In this paper, we describe the morphology, thermal and shape memory behavior of methyl vinyl silicone rubber (MVMQ)/olefin block copolymer (OBC) blends prepared by a melt-blending and chemical cross-linking method. MVMQ without crystalline domains could not hold its temporary shape. After introducing the OBC, the obtained blends exhibited excellent dual shape memory properties. The cross-linking networks of MVMQ acted as reversible domains, while crystalline regions of OBC worked as fixed domains. When the blending ratio of MVMQ/OBC was 50/ 50, the blend had both a high shape fixity ratio and shape recovery ratio.


2018 ◽  
Vol 11 (03) ◽  
pp. 1850047 ◽  
Author(s):  
Junrui Zhang ◽  
Guojun Jiang ◽  
Tianhao Huang

In this study, we synthesized semi-crystalline thermosetting polymer that have two-way-reversible shape memory effect (2W-SME) with a single crystalline phase and an amorphous phase. The polymer could be synthesized readily and its glass transition temperature (Tg) could be tuned over a wide range. The effect of acrylic monomers on the degree of cross-linking, the effects of different conditions, the applied stress, the acrylic monomers used, and the phase ratio of the crystalline and amorphous domains on the 2W-SME were studied. Measurement results confirmed that the polymer showed the 2W-SME and, the strongest 2W-SME achieved under the optimized conditions corresponded to a reversible deformation of 8.5%.


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