Synthesis of ultra-small branched star poly(ε-caprolactone)s and their high end group concentration effects on crystallization

Abstract

We successfully synthesize the three-and sixbranched star poly(e-caprolactone)s with extremely small branched segments (USB-SPCLs) using a facile pseudo-one-pot process in a pilot scale and investigate the effect of ultra-small branches on their crystallization behaviors. The number of branched segments and the individual branched segment lengths for USB-SPCLs are precisely controlled via manipulating monomer-to-core ratio, adjusting monomer-to-polymer conversion, end-capping the terminal hydroxyl groups, and vacuum purification, which results in USB-SPCLs having the branched segments below five degree of polymerization with a high yield exceeding 93%. The molecular weights obtained from 1 H NMR spectroscopy are consistent with that obtained from MALDI-TOF-MS and the molecular weight distributions are narrow with M w /M n 1.2, indicating that USB-SPCLs have mono-dispersed branches. USB-SPCLs have low melting temperatures and broad double-melting peaks attributed to their extremely small branches, and the crystallization behaviors for USB-SPCLs depend on the end group concentration. On the other hand, the glass transitions for USB-SPCLs depend on the total molecular weights, regardless of the number and length of branched segments.

Super-tough self-healable multiphasic supramolecular plastic via sequence-biased statistical copolymerization

“…3b and Table S4 †). This indicated that the PCL chain-folding crystallization in the USPCDs was hindered by the incorporation of the amorphous branch PDL segments, 62 which agrees well with the ultraviolet-visible (UV-vis) spectroscopy results; the light transmittance values of the USPCDs increased as the molar fraction of PDL increased owing to the reduction in the crystallinity (Fig. S6 †).…”

Preparation of Degradable and Transformable Core–Corona-Type Particles that Control Cellular Uptake by Thermal Shape Change

“…As a result, the melting behavior is a combination of the melting of the original crystal, heat of recrystallization, and melting of the recrystallized polymer. 40,41 Therefore, two endothermic peaks are observed. In subsequent experiments, 3PCL-5 was used, which had a T m of 37.8 °C, which is close to the body temperature.…”

“…The heating process yielded two broad peaks, whereas the cooling process yielded one peak. These results are similar to those reported in previous studies. , These two peaks may be due to the formation of cyclic byproducts through the backbiting reaction of the terminal OH group to the ester group in the ring-opening polymerization of CL without terminal control. Therefore, the endothermic peak broadened owing to the contamination of cyclic byproducts and changes in the crystalline structure.…”

“…Therefore, the melting behavior has an exothermic peak due to recrystallization and an endothermic peak due to the melting of the recrystallized polymer. As a result, the melting behavior is a combination of the melting of the original crystal, heat of recrystallization, and melting of the recrystallized polymer. , Therefore, two endothermic peaks are observed. In subsequent experiments, 3PCL-5 was used, which had a T m of 37.8 °C, which is close to the body temperature.…”

Additives to prevent the formation of surface defects during poly(vinyl chloride) calendering

“…[ 23, 30 ] Due to the similarity in structure between PCL 540 ‐Acet and PCL 540 ‐triol, PCL 540 ‐Acet was used as a compatible substitute to investigate the contribution of the PCL 540 ‐triol group to gas check removal. Upon blending PCL 540 ‐Acet with PVC at 55 phr, it was observed that film formation occurred during regular time frames, resulted in no oily residue on the film, and the film was flexible, thereby confirming its compatibility with PVC, as reported by Choi et al [ 30 ] However, similar to DHPS, PCL 540 ‐Acet did not remove gas checks, producing films with an average of 6122 gas checks per m 2 of film (Figure 4), which is significantly higher than PCL 540 ‐Succ‐C7 ( p < 0.05), but also showed no decrease compared to the DINP control ( p > 0.05). Taken together, these results suggest that the observed phenomenon of gas check‐free films had arisen due to the unique chemical structure of PCL 540 ‐Succ‐C7 as a whole, and not due to its individual constituents.…”