Interfacial Entanglements between Glassy Polymers Investigated by Nanofractography with High-Resolution Scanning Electron Microscopy

Abstract

Fracture surfaces created during the interfacial failure of weak interfaces between glassy polymers were investigated with high-resolution scanning electron microscopy (HR-SEM). As reported in an earlier communication (Macromol. Rapid Commun.200728915921), we found that interfacial failures between immiscible polymers produced large number of nanosized fibrils on the fracture surfaces. In order to investigate the mechanism of such ultra small structure formation in the crack propagation process, welding experiments of monodispersed polystyrenes with different molecular weights were employed by the asymmetric double cantilever beam (ADCB) test. The “nano-fibrils” were produced during the fractures of the interfaces between polystyrenes with the molecular weight higher than 2000, of which thickness was comparable to the entanglement spacing. It was found that the “nano-fibrous” formation bearing in the crack propagation reflected the local entanglement structures formed at narrow interfaces comparable to the entanglement spacing.

Morphology, Molecular Dynamics, and Interfacial Phenomena in Systems Based on Silica Modified by Grafting Polydimethylsiloxane Chains and Physically Adsorbed Polydimethylsiloxane

“…A main result of the present study is that the grafted polymer forms practically the inner “dead” interfacial layer (Section ), whereas the additional physically adsorbed polymer makes mainly an outer layer and exhibits a distinct dynamics in BDS (α int relaxation) (Scheme b). , This situation is compatible with previous experimental findings in polymers adsorbed on solid surfaces (and fillers). ,, Work by computer simulations is in progress, aiming at further clarifying this point. Experimental results by structural characterization techniques (e.g., SAXS, HR-SEM, SANS) ,,,,, in future may shed more light on organization and dynamics of interfacial polymer. Also, work on similar to here PNCs by employing, however, a different type of grafting process avoiding chain breaking, as well as by using slightly modified polysiloxanes, such as poly­(hydroethyl siloxane) and poly­(methyl phenyl siloxane), in addition to replacing the methyl end groups of PDMS by hydroxyls would be helpful.…”

“…34,38,41 Work by computer simulations is in progress, aiming at further clarifying this point. Experimental results by structural characterization techniques (e.g., SAXS, HR-SEM, SANS) 16,33,34,63,98,99 in future may shed more light on organization and dynamics of interfacial polymer. Also, work on similar to here PNCs by employing, however, a different type of grafting process avoiding chain breaking, 12 as well as by using slightly modified polysiloxanes, such as poly-(hydroethyl siloxane) and poly(methyl phenyl siloxane), 100 in addition to replacing the methyl end groups of PDMS by hydroxyls 35 would be helpful.…”

Study on Welding Mechanism Based on Modification of Polypropylene for Improving the Laser Transmission Weldability to PA66

“…Lo et al developed a kinetic model to describe the behavior of semicrystalline polymer interfaces [ 20 ]. Horiuchi et al investigated interfacial entanglements between glassy polymers [ 21 ]. It can be concluded that when dissimilar polymers are welded, the main mechanism for the improvement of welding strength includes mutual diffusion and molecular entanglement at the interface of the upper materials and the lower materials [ 19 , 20 , 21 ].…”

“…Horiuchi et al investigated interfacial entanglements between glassy polymers [ 21 ]. It can be concluded that when dissimilar polymers are welded, the main mechanism for the improvement of welding strength includes mutual diffusion and molecular entanglement at the interface of the upper materials and the lower materials [ 19 , 20 , 21 ]. For one thing, the above reactions will reduce interfacial tension between TGMPP and PA66 and increase their compatibility which makes them easy to diffuse mutually.…”

Confocal raman spectroscopy studies on the mutual diffusion behavior at the interface between two different polyesters

“…That is, the interfacial behavior in polymer blends has been a topic of intensive research. Various techniques, including neutron reflectometry , ellipsometry , secondary‐ion mass spectrometry , Raman spectroscopy , infrared spectroscopy , X‐ray reflectometry , and energy‐filtering transmission electron microscopy , have been used to analyze the interfacial behavior in polymer blends. In the case of core–shell‐structured toner for electrophotography, two polyesters with different chemical structures, different T g s, or different molecular weights are often used to fabricate the core–shell structures.…”