In Situ synthesis of multiblock copolymers of poly(ϵ‐caprolactone) with different poly(ether diols) based polyurethane by reactive extrusion

Abstract

Polyurethanes with multiblock copolymers of poly(e-caprolactone) (PCL) and poly(tetramethylene oxide) glycol (PTMG) or poly(ethylene glycol) (PEG) as a soft segment were synthesized in situ via reactive extrusion from e-caprolactone (CL) and 4,4 0 -diphenylmethane diisocyanate (MDI). The titanium alkoxide mixture generated from an ester-exchange reaction between titanium propoxide [Ti(OPr) 4 ], and excessive PTMG or PEG was used as an initiator and catalyst. Compared to the reported fabrication of polycaprolactone-based polyurethane (PCLU), the in situ reactive extrusion preparation not only explored a new rapid route for the fabrication of PCLU but also offered a simplified, controllable approach for the production of PCLU in a successive mass scale. A series of PTMG-PCLUs and PEG-PCLUs with different PCL block-average degrees of polymerization (DP n 's) were prepared by only an adjustment of the relative concentration of CL in the reaction system, with a certain constant molar ratio of MDI to titanium alkoxide.1 H-NMR, gel permeation chromatography, and differential scanning calorimetry results indicate that all of the CL monomers were converted in the polymerization, and the molecular weight of the copolymers was about 8 Â 10 4 g/mol with a polydispersity index of approximate 2.4. With an increase in the PCL block-average DP n in PTMG-PCLU from 25 to 40, the tensile strength increased from 16.5 to 22.7 MPa, and the melting point increased from 46.1 to 49.5 C. It was also verified by PEG-PCLU prepared with organic Ti of lowered content in the initiator mixture that the mechanical properties could be greatly affected and dropped with decreasing content of organic Ti in the initiator mixture.

Influence and prediction of processing parameters on the properties of microcellular injection molded thermoplastic polyurethane based on an orthogonal array test

“…Thus, the properties of TPU can be tuned by changing the components and ratios of soft and hard segments to yield a wide range of polyurethanes that vary from thermoplastic elastomers to rigid thermoset foams. 5 Polyurethane foams can be mass produced by reaction extrusion 6 and reaction injection. 7 Other methods to produce porous polyurethane structures without a chemical reaction for medical applications (e.g., tissue engineering scaffolds) include solvent casting/particle leaching, 8 thermally induced phase separation, 9 electrospinning, 10 gas foaming, 11 and rapid prototyping.…”

Shape memory properties of polycaprolactone‐based polyurethanes prepared by reactive extrusion

“…PCLU samples used in this study were obtained from polyether diol (PTMG or PEG) according to our previous work34 by reactive extrusion in the corotating twin screw extruder of which the barrel temperature profile between the hopper and the die was 190°C, and the rotating rate was 100 r/min. A typical experimental procedure was as follows: a calculated amount of Ti(OPr) 4 mixture modified by polyether diol and MDI were dissolved in CL monomer to make the “Solution A” and “Solution B,” respectively.…”

“…According to different polyether diols from which PCLUs originated, different PCLU pellets were obtained, PTMG1000‐DPn25, PTMG1000‐DPn30, PTMG1000‐DPn35, PTMG1000‐DPn40, PEG1000‐DPn20, PEG1000‐DPn25, PEG1000‐DPn30, PEG1000‐DPn35, PEG1000‐DPn40, PEG400‐DPn20, PEG400‐DPn25, PEG400‐DPn30, PEG400‐DPn35, PEG400‐DPn40, PEG4000‐DPn12, PEG4000‐DPn21, and PEG4000‐DPn25. The reaction mechanism, monomer conversion, molecular weight, and structure were reported in another article34.…”