How the Aliphatic Glycol Chain Length Determines the Pseudoeutectic Composition in Biodegradable Isodimorphic poly(alkylene succinate--caprolactone) Random Copolyesters.

We synthesize four series of novel biodegradable poly(alkylene succinate--caprolactone) random copolyesters using a two-step ring-opening/transesterification and polycondensation process with ε-caprolactone (PCL) as a common comonomer. The second comonomers are succinic acid derivatives, with variations in the number of methylene groups () in the glycol segment, = 2, 4, 8, and 12. The obtained copolyesters were poly(ethylene succinate--PCL) (ESCL), poly(butylene succinate--PCL) (BSCL), poly(octamethylene succinate--PCL) (OSCL), and poly(dodecylene succinate--PCL) (DSCL).

Sequential Crystallization and Multicrystalline Morphology in PE--PEO--PCL--PLLA Tetrablock Quarterpolymers.

We investigate for the first time the morphology and crystallization of two novel tetrablock quarterpolymers of polyethylene (PE), poly(ethylene oxide) (PEO), poly(ε-caprolactone) (PCL), and poly(l-lactide) (PLLA) with four potentially crystallizable blocks: PE PEO PCL PLLA (Q1) and PE PEO PCL PLLA (Q2) (superscripts give number average molecular weights in kg/mol, and subscripts give the composition in wt %). Their synthesis was performed by a combination of polyhomologation (C1 polymerization) and ring-opening polymerization techniques using a ″catalyst-switch″ strategy, either ″organocatalyst/metal catalyst switch″ (Q1 sample, 96% isotactic tetrads) or ″organocatalyst/organocatalyst switch″ (Q2 sample, 84% isotactic tetrads). Their corresponding precursors-triblock terpolymers PEPEOPCL, diblock copolymers PEPEO, and PE homopolymers-were also studied.

Structure and Properties of Reactively Extruded Opaque Post-Consumer Recycled PET.

The recyclability of opaque PET, which contains TiO nanoparticles, has not been as well-studied as that of transparent PET. The objective of this work is to recycle post-consumer opaque PET through reactive extrusion with Joncryl. The effect of the reactive extrusion process on the molecular structure and on the thermal/mechanical/rheological properties of recycling post-consumer opaque PET (r-PET) has been analyzed.

Crystallization and Morphology of Triple Crystalline Polyethylene--poly(ethylene oxide)--poly(ε-caprolactone) PE--PEO--PCL Triblock Terpolymers.

The morphology and crystallization behavior of two triblock terpolymers of polymethylene, equivalent to polyethylene (PE), poly (ethylene oxide) (PEO), and poly (ε-caprolactone) (PCL) are studied: PE--PEO--PCL (T1) and PE--PEO--PCL (T2) (superscripts give number average molecular weights in kg/mol and subscripts composition in wt %). The three blocks are potentially crystallizable, and the triple crystalline nature of the samples is investigated. Polyhomologation (C1 polymerization), ring-opening polymerization, and catalyst-switch strategies were combined to synthesize the triblock terpolymers.

Accelerating the crystallization kinetics of linear polylactides by adding cyclic poly (L-lactide): Nucleation, plasticization and topological effects.

Polylactide is one of the most versatile biopolymers, but its slow crystallization limits its temperature usage range. Hence finding ways to enhance it is crucial to widen its applications. Linear and cyclic poly (L-lactide) (l-PLLA and c-PLLA) of similarly low molecular weights (MW) were synthesized by ring-opening polymerization of L-lactide, and ring-expansion methodology, respectively.

Controlling the Isothermal Crystallization of Isodimorphic PBS--PCL Random Copolymers by Varying Composition and Supercooling.

In this work, we study for the first time, the isothermal crystallization behavior of isodimorphic random poly(butylene succinate)--poly(ε-caprolactone) copolyesters, PBS--PCL, previously synthesized by us. We perform nucleation and spherulitic growth kinetics by polarized light optical microscopy (PLOM) and overall isothermal crystallization kinetics by differential scanning calorimetry (DSC). Selected samples were also studied by real-time wide angle X-ray diffraction (WAXS).

The Effect of Titanium Dioxide Surface Modification on the Dispersion, Morphology, and Mechanical Properties of Recycled PP/PET/TiO PBNANOs.

Titanium dioxide (TiO) nanoparticles have recently appeared in PET waste because of the introduction of opaque PET bottles. We prepare polymer blend nanocomposites (PBNANOs) by adding hydrophilic (hphi), hydrophobic (hpho), and hydrophobically modified (hphoM) titanium dioxide (TiO) nanoparticles to 80rPP/20rPET recycled blends. Contact angle measurements show that the degree of hydrophilicity of TiO decreases in the order hphi > hpho > hphoM.

Synthesis and Characterization of Double Crystalline Cyclic Diblock Copolymers of Poly(ε-caprolactone) and Poly(l(d)-lactide) (c(PCL-b- PL(D)LA)).

The synthesis of symmetric cyclo poly(ε-caprolactone)-block-poly(l(d)-lactide) (c(PCL-b-PL(D)LA)) by combining ring-opening polymerization of ε-caprolactone and lactides and subsequent click chemistry reaction of the linear precursors containing antagonist functionalities is presented. The two blocks can sequentially crystallize and self-assemble into double crystalline spherulitic superstructures. The cyclic chain topology significantly affects both the nucleation and the crystallization of each constituent, as gathered from a comparison of the behavior of linear precursors and cyclic block copolymers.