A Methodology of Hydrodynamic Complexity in Topologically Hyper‐Branched Polymers Undergoing Hierarchical Multiple Relaxations

Lu, Haibao; Wang, Xiaodong; Hossain, Mokarram; Fu, Yong Qing

doi:10.1002/macp.202000052

Cited by 5 publications

(5 citation statements)

References 38 publications

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“…More importantly, the presence of solvents can significantly expand the breadth of the relaxation spectrum, which may be attributed to the change of strength of intermolecular interaction caused by the chemical or physical bonding newly formed between solvent and polymer molecules [ 27 ]. This raises more challenges for developing theories for the glass transition behaviors of polymers and polymer–solvent systems [ 32 , 33 ].…”

Section: Discussionmentioning

confidence: 99%

Glass Transition Behavior of Wet Polymers

2021

Materials

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We have performed a systematical investigation on the glass transition behavior of amorphous polymers with different solvent concentrations. Acrylate-based amorphous polymers are synthesized and treated by isopropyl alcohol to obtain specimens with a homogenous solvent distribution. The small strain dynamic mechanical tests are then performed to obtain the glass transition behaviors. The results show that the wet polymers even with a solvent concentration of more than 60 wt.% still exhibit a glass transition behavior, with the glass transition region shifting to lower temperatures with increasing solvent concentrations. A master curve of modulus as a function of frequency can be constructed for all the polymer–solvent systems via the time–temperature superposition principle. The relaxation time and the breadth of the relaxation spectrum are then obtained through fitting the master curve using a fractional Zener model. The results indicate that the breadth of the relaxation spectrum has been greatly expanded in the presence of solvents, which has been rarely reported in the literature. Thus, this work can potentially advance the fundamental understanding of the effects of solvent on the glass transition behaviors of amorphous polymers.

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Section: Discussionmentioning

confidence: 99%

Glass Transition Behavior of Wet Polymers

2021

Materials

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“…Because of their broad prospect in the areas of the automotive industry, smart medical devices, and self-driven actuators applicable to aeronautics and astronautics, shape memory polymers (SMPs) have attracted plenty of attention in recent 40 years (Leng et al, 2011; Nourian et al, 2022; Wan et al, 2022). As a kind of smart material, the shape memory properties of SMPs can be triggered by temperature, electricity, moisture, light, etc., without the application of external force (Lu et al, 2020; Sun et al, 2021; Wang et al, 2018; Zhao et al, 2019). Compared with other shape memory materials, such as shape memory alloys and shape memory ceramics, the primary advantages of SMPs are ease of processing, lightweight, and large recoverable deformation (up to 400% strain) (Yu and Young, 2019).…”

Section: Introductionmentioning

confidence: 99%

Thermo-mechanical modeling of semicrystalline triple shape memory polymers

Bian

Cai

et al. 2023

Journal of Intelligent Material Systems and Structures

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Compared with amorphous shape memory polymers (SMPs), semicrystalline SMPs have more diverse shape memory effects (SMEs) which promotes their application in smart structures. To reveal the driving mechanism of the triple SMEs of semicrystalline SMPs, our study focuses on developing the constitutive model under the condition of finite deformation. In the paper, a thermo-mechanical constitutive model under consideration of the second law of thermodynamics is developed based on the theory of thermodynamics with internal state variables. The model can be used to describe the nonequilibrium response of the amorphous and semicrystalline components in the vicinity of the glass transition, melting, and crystallization. To verify the validity of model, numerical simulation is carried out for a thermo-mechanical shape memory cycle which can be divided into a two-step programing process and a two-step recovery process. The comparison between the model results and the test data shows good agreement.

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“…The successful application of smart materials has greatly promoted the development of relevant industrial areas. As a class of smart materials, shape memory polymers (SMPs) and shape memory polymer composites (SMPCs) can be used in intelligent medical devices, self-driven actuators and 4D printing industry [1][2][3] by utilizing the shape memory effects (SMEs) triggered by the environmental stimuli [4][5][6][7][8][9]. In comparison with other shape memory materials, SMPs and SMPCs have the advantages of light weight, low cost, and ease of manufacturing.…”

Section: Introductionmentioning

confidence: 99%