Preparation and characterization of in situ polymerized cyclic butylene terephthalate/graphene nanocomposites

Abstract

Graphene reinforced cyclic butylene terephthalate (CBT) matrix nanocomposites were prepared and characterized by mechanical and thermal methods. These nanocomposites containing different amounts of graphene (up to 5 wt%) were prepared by melt mixing with CBT that was polymerized in situ during a subsequent hot pressing. The nanocomposites and the neat polymerized CBT (pCBT) as reference material were subjected to differential scanning calorimetry (DSC), dynamical mechanical analysis (DMA), thermogravimetrical analysis (TGA) and heat conductivity measurements. The dispersion of the grapheme nanoplatelets was characterized by transmission electron microscopy (TEM). It was established that the partly exfoliated graphene worked as nucleating agent for crystallization, acted as very efficient reinforcing agent (the storage modulus at room temperature was increased by 39 and 89% by incorporating 1 and 5 wt.% graphene, respectively). Graphene incorporation markedly enhanced the heat conductivity but did not influence the TGA behaviour due to the not proper exfoliation except the ash content.

In Situ Polymerized pCBT Composites with Aligned Carbon Nanotube Buckypaper: Structure and Properties

“…Over most of the temperature ranges tested, the storage modulus increased with increasing nanotube content. A similar phenomenon was observed in graphene/pCBT composites . With 64 wt% aligned buckypaper loading, the composite sample (64BPmx) exhibits a storage modulus of approximately 84.7 GPa at room temperature while that of the neat pCBT sample is only 2.1 GPa.…”

“…pCBT may have great importance for “all‐PBT” composites. The thermoplastic nature of pCBT may provide a low‐capital route to a new family of pCBT‐based recyclable materials made using a range of plastic processing technologies …”

Effect of processing conditions on the thermal and electrical conductivity of poly (butylene terephthalate) nanocomposites prepared via ring-opening polymerization

“…Furthermore, the exploitation of GRM was described to improve mechanical, electrical and thermal properties [30,42,43,45]. Indeed, in a previous paper we reported a 12-fold increase in the thermal conductivity when 30 wt.% of GNP is added to pCBT, while the addition of 5 wt.% of rGO annealed at 1700°C led up to a 4-fold increase [30].…”

“…Recently, the preparation of polymer nanocomposites was obtained by in-situ ring-opening polymerization of cyclic butylene terephthalate (CBT) oligomers into poly (butylene terephthalate), pCBT [38], taking advantage of both the extremely low viscosity of CBT and of the viscosity increase occuring during polymerization, to disperse nanoparticles, including organoclays [39], carbon nanotubes [40], silica [41] and graphenerelated materials [30, 42]. The presence of GRM was reported to affect the polymerization kinetic of CBT, with increase of the polymerization time [43] and decrease of the average molecular weight [44].Furthermore, the exploitation of GRM was described to improve mechanical, electrical and thermal properties [30,42,43,45]. Indeed, in a previous paper we reported a 12-fold increase in the thermal conductivity when 30 wt.% of GNP is added to pCBT, while the addition of 5 wt.% of rGO annealed at 1700°C led up to a 4-fold increase [30].In this work, the optimization of different processing paremeters in the preparation of pCBT nanocomposites through ring-opening polymerization of CBT is addressed.…”

A Review of the Recent Advances in Cyclic Butylene Terephthalate Technology and its Composites

“…Polymerized CBT XB3-CA4 exhibited an Avrami exponent of n≈2, indicating two dimensional plate-like crystal growth. The crystallisation half times of polymerized CBT160 were in the range of 0.5-1.5 min for isothermal crystallization at [190][191][192][193][194][195] °C, respectively, and increased with crystallization temperature. Slightly longer crystallisation half times were found for polymerized CBT XB3-CA4.…”