Hyperbranched Polyamine as Multipurpose Polymeric Additives for LDPE and Plasticized PVC

The hyperbranched polyamine based on 4,4'-sulfonyl dianiline was obtained by the earlier reported method and used as multipurpose polymeric additives for low density polyethylene (LDPE) and plasticized polyvinyl chloride (PVC). The effect of this hyperbranched polyamine on the processability, mechanical properties, flammability behavior, etc. has been studied. The mechanical properties of the compounded polymers before and after thermal aging and leaching in different chemical media were also studied at dose levels of 1 to 7.5% (w/w) of the additive. SEM study indicates that both polymers exhibit homogenous morphology at all dose levels. The mechanical properties like tensile strength (T.S.) and hardness are improved by incorporation of hyperbranched polymeric additive and these properties increased with the increase of dose level. The flame-retardant behavior as measured by limiting oxygen index (LOI) of all samples indicates an enhanced LOI value compared to the polymer without hyperbranched additive. The processing behavior of all compounded polymers was investigated by measurement of solution viscosity and MFR value. The effect of leaching and heat aging of the polymers on the mechanical properties showed that hyperbranched polyamine is better compared to the commercially used antidegradant, N-isopropyl-Nphenyl p-phenylene diamine (IPPD)

Synthesis of multi-walled carbon nanotube/polyhedral oligomeric silsesquioxane nanohybrid by utilizing click chemistry

A new hybrid material consisting of a polyhedral oligomeric silsesquioxane (POSS) and carbon nanotube (CNT) was synthesized by a simple and versatile approach entailing click coupling between azide moiety-functionalized POSS and alkyne-functionalized multi-walled CNTs. This approach provides a simple and convenient route to efficiently functionalize a wide variety of nanoscale nanostructure materials on the surface of CNTs

High-Speed Actuation and Mechanical Properties of Graphene-Incorporated Shape Memory Polyurethane Nanofibers

We prepared poly­(ε-caprolactone) (PCL)-based shape memory polyurethane (PU) nanofibers incorporating three kinds of graphene, that is, graphene oxide (GO), PCL-functionalized graphene with PCL (f-GO), and reduced graphene (r-GO) to investigate their mechanical and shape memory properties. Incorporation of graphene into the PU nanofibers increased the modulus and breaking stress compared to that of pure PU nanofibers. In particular, the f-GO nanofibers showed the largest enhancement in mechanical properties because of increased interaction between graphene and the polymer matrix. In the shape memory test, f-GO or r-GO-incorporated PU nanofibers showed actuation speed that was much faster than that of pure PU nanofibers. The shape recovery time of 1 wt % f-GO or r-GO nanofibers was 8 s, whereas that of the PU nanofibers and GO-incorporated nanofibers were 27 and 13 s, respectively. This study demonstrates that incorporation of f-GO into shape memory PU nanofibers can be used effectively to achieve both high-speed shape recovery and high mechanical strength