Correlation between molecular weight and confined crystallization behavior of polymers grafted onto a zero-dimensional filler

Abstract

In this work, polymer chains of different molecular weights are grafted onto a zero-dimensional filler.

Influence of synthesis conditions on molecular weight as well as mechanical and thermal properties of poly(hexamethylene 2,5-furanate)

“…Besides, as the free volume continues to increase along with increasing temperature, the glass transition occurs where large chain segments start moving, whereby the transition is dependent on the degree of polymerization or the critical molecular weight [28,29]. Additionally, Hao et al [30] found that the higher the molecular mass, the stronger the crystallization ability, which is in the agreement with the observations made herein. Moreover, the values of heat capacities, corresponding to T g , are in the agreement with the estimations of the crystallinity degree, since T g occurs in either amorphous materials or amorphous region in the materials, so the corresponding heat capacities exhibited lower values for materials with higher M w , and thus T g and X c (PHF_2).…”

“…It is well established that the tensile properties such as tensile strength and elongation at break increase with the increase of molecular weight or narrowing molecularweight distribution. This effect reaches a limit at a certain and relatively high M w , where there is no longer any significant change in mechanical properties with increasing M w [29][30][31][32]. The stress-strain curves of the synthesized PHFs are collected in Figure 2, and the corresponding results are summarized in Table 1.…”

Simulations on polymer nanocomposite crystallization

“…119,120 The detailed microscopic mechanisms of the influence of molecular weight Reprinted with permission from Nie et al 123 Copyright (2016) Elsevier on the crystallization behaviors of grafted polymers have also been further revealed by molecular simulations. 127,128 For example, our group reported that the increasing molecular weight leads to shorter nucleation induction period and higher final crystallinity, which is consistent with the experimental results. 127 In addition, the nucleation mode and the orientation of crystalline stems are also affected by molecular weight.…”

“…In the PCL systems grafted onto MWNT, Zhou, and coworkers also observed that the growth of molecular weight can reduce the activation energy of crystallization 119,120 . The detailed microscopic mechanisms of the influence of molecular weight on the crystallization behaviors of grafted polymers have also been further revealed by molecular simulations 127,128 . For example, our group reported that the increasing molecular weight leads to shorter nucleation induction period and higher final crystallinity, which is consistent with the experimental results 127 .…”

“…In addition, the nucleation mode and the orientation of crystalline stems are also affected by molecular weight. It has been reported that the chain segments prefer to choose the intermolecular nucleation mode in the grafted polymer systems with lower molecular weight, while the chain segments exhibit the intramolecular nucleation in the grafted polymer systems with higher molecular weight 127,128 . The difference in nucleation modes can be attributed to the limiting effect from grafting points.…”