Daria Pawlikowska

This work reports a study on the influence of graphene oxide (GO) and reduced graphene oxide (rGO) on the functional properties of poly(trimethylene terephthalate)-block-poly(caprolactone) (PTT-block-PCL-T) (75/25 wt.%/wt.%) copolymer, obtained from dimethyl terephthalate (DMT), 1,3-biopropanediol and polycaprolactone diol (PCL) via in situ polymerization. The article presents, if and how the reduction of graphene oxide, in comparison to the non-reduced one, can affect morphological, thermal, electrical and mechanical properties. SEM examination confirms/reveals the homogeneous distribution of GO/rGO nanoplatelets in the PTT-block-PCL-T copolymer matrix. More than threefold increase in the value of the tensile modulus is achieved by the addition of 1.0 wt.% of GO and rGO. Moreover, the thermal conductivity and thermal stability of the GO and rGO-based nanocomposites are also improved. The differential scanning calorimetry (DSC) measurement indicates that the incorporation of GO and rGO has a remarkable impact on the crystallinity of the nanocomposites (an increase of crystallization temperature up to 58 °C for nanocomposite containing 1.0 wt.% of GO is observed). Therefore, the high performances of the PTT-block-PCL-T-based nanocomposites are mainly attributed to the uniform dispersion of nanoplatelets in the polymer matrix and strong interfacial interactions between components.

The series of poly(trimethylene terephthalate)‐block‐PCLT (PTT‐block‐PCLT) copolymers with different contents of PTT as rigid, and poly(caprolactone) (PCL) as flexible segments have been synthesized from dimethyl terephthalate (DMT), 1,3‐bio‐propanediol, and PCL diol) in a two‐step process involving transesterification and polycondensation in the melt. The weight amount of flexible PCLT segments varied from 0 (homopolymer PTT), 25, 35 to 45%. The molecular structure of the synthesized copolymers was confirmed by nuclear magnetic resonance and Fourier transform infrared spectroscopy analyses. According to Hoy's method, one confirmed that PTT and PCL are likely miscible, as the difference of the solubility parameters of PTT and PCL block pairs, equals to 3.15 MPa^1/2. Moreover, the phase structure and mutual miscibility for the series of PTT‐block‐PCLT copolymers was characterized by differential scanning calorimetry, dynamic mechanical thermal analysis, and wide‐angle X‐ray scattering measurements. In copolymers with 35 and 45 wt % of flexible segments, the crystalline phase is formed during annealing above glass‐transition temperature of copolymer. These copolymers during cooling at the standard rate do not crystallize. It was also found that incorporation of PCLT flexible segments, due to the macrophase separated structure, cause the decrease of the melting point and glass‐transition temperature, along with the tensile modulus and tensile strength of PTT‐block‐PCLT copolymers, and at the same time cause an increase in the value of the elongation at break. As a result of copolymerization of PTT with PCLT, one obtained multiblock copolymers with a heterophase structure. By changing the PTT/PCLT ratio, one obtained copolymers that differ in hardness and tensile strength. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47341.

In this paper, the electrical and thermal conductivity and morphological behavior of low density polyethylene (LDPE)/multi-walled carbon nanotubes (MWCNTs) + graphene nanoplatelets (GNPs) hybrid nanocomposites (HNCs) have been studied. The distribution of MWCNTs and the hybrid of MWCNTs/GNPs within the polymer matrix has been investigated with scanning electron microscopy (SEM). The results showed that the thermal and electrical conductivity of the LDPE-based nanocomposites increased along with the increasing content of carbon nanofillers. However, one could observe greater improvement in the thermal and electrical conductivity when only MWCNTs have been incorporated. Moreover, the improvement in tensile properties and thermal stability has been observed when carbon nanofillers have been mixed with LDPE. At the same time, the increasing content of MWCNTs and MWCNTs/GNPs caused an increase in the melt viscosity with only little effect on phase transition temperatures.

Two series of reactive polymer blends based on post-consumer glycol-modified poly(ethylene terephthalate) (PETG) and poly(tetramethylene oxide) (PTMO) were prepared in order to investigate the possibility of utilization of waste PETG foils from the packaging industry. The resulting copolymer consisted of hard segments based on PETG and soft segments of PTMO, the latter accounted for 25, 35 or 50 percent of the total mass. The effects of the content and length of the soft segments derived from poly(oxybutylene) glycol, with molecular weights of 1000 or 2000, on the structure and thermal properties of the resulting materials were investigated. Przygotowano dwie serie reaktywnych mieszanin polimerowych na bazie poużytkowej folii z poli(tereftalanu etylenu) modyfikowanego glikolem (PETG) oraz poli(tlenku tetrametylenu) (PTMO) w celu zbadania możliwości zagospodarowania odpadowych folii PETG z przemysłu opakowaniowego. PETG stanowił w kopolimerze segmenty sztywne, a PTMO segmenty giętkie, których udział wynosił 25, 35 lub 50 % mas. Zbadano wpływ udziału segmentów giętkich oraz długości ich łańcuchów, pochodzących z glikolu polioksybutylenowego o masie molowej odpowiednio 1000 g/mol lub ­2000 g/mol, na strukturę oraz właściwości termiczne otrzymanych materiałów.

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informuj?ce swoich czytelnik?w o najnowszych osi?gni?ciach naukowych i nowoczesnych rozwi?zaniach technicznych w Polsce i na ?wiecie, popularyzuje problemy techniczne oraz poszerza wiedz? i kultur? techniczn?.

A series of PETG-block-PTMO copolymers were synthesized by means of a polycondensation process and characterized using¹H nuclear magnetic resonance and Fourier transform infrared spectroscopy, that confirm the successful synthesis of the material.

The development and further studies on several types of graphene nanoplatelets (GNP) have enabled manufacture of electrically conductive and reinforced polymer nanocomposites with enhanced gas barrier performance at extremely low loading. Herein, we present the synthesis process, morphology and gas barrier properties of the glycol modified poly(ethylene terephthalate) (PETG) based nanocomposites. For the first time, we compared how different types of GNPs, at the same nanofiller's content of 0.5 wt %, affect the properties of polymer matrix obtained by in situ polymerization.