@article{LiangBehlLuetzowetal.2021,
  author    = {Liang, Xiao and Behl, Marc and L{\"u}tzow, Karola and Lendlein, Andreas},
  title     = {Cooligomers from morpholine-2,5-dione and para-dioxanone and catalyst complex SnOct(2)/2-hydroxyethyl sulfide},
  series = {MRS advances : a journal of the Materials Research Society (MRS)},
  volume    = {6},
  journal   = {MRS advances : a journal of the Materials Research Society (MRS)},
  number    = {32},
  publisher = {Springer},
  address   = {Heidelberg},
  issn      = {2059-8521},
  doi       = {10.1557/s43580-021-00082-5},
  pages     = {764 -- 768},
  year      = {2021},
  abstract  = {Complexes from catalysts and initiator can be used to insert a specific number of additional chemical functional groups in (co)polymers prepared by ring-opening polymerization (ROP) of lactones. We report on the synthesis of cooligomers from sec-butyl-morpholine-2,5-dione (SBMD) and para-dioxanone (PDX) by ROP with varied feed ratios in the bulk using the catalyst complex SnOct(2)/2-hydroxyethyl sulfide. M-n of the cooligomers (determined by GPC) decreased with decreasing SBMD feed ratio from 4200 +/- 420 to 800 +/- 80 g mol(-1). When the feed ratio was reduced from 80 to 50 mol\% the molar ratio of SBMD of the cooligomers (determined by H-1-NMR) remained nearly unchanged between 81 and 86 mol\% and was attributed to a higher reactivity of SBMD. This assumption was confirmed by fractionation of GPC, in which an increase of SBMD with increasing molecular weight was observed. The catalyst/initiator system provides a high potential to create orthogonal building blocks by cleavage of the sulfide bond.},
  language  = {en}
}
@article{BehlBalkLuetzowetal.2021,
  author    = {Behl, Marc and Balk, Maria and L{\"u}tzow, Karola and Lendlein, Andreas},
  title     = {Impact of block sequence on the phase morphology of multiblock copolymers obtained by high-throughput robotic synthesis},
  series = {European polymer journal : EPJ},
  volume    = {143},
  journal   = {European polymer journal : EPJ},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0014-3057},
  doi       = {10.1016/j.eurpolymj.2020.110207},
  pages     = {9},
  year      = {2021},
  abstract  = {The chemical nature, the number length of integrated building blocks, as well as their sequence structure impact the phase morphology of multiblock copolymers (MBC) consisting of two non-miscible block types. We hypothesized that a strictly alternating sequence should favour phase segregation and in this way the elastic properties. A library of well-defined MBCs composed of two different hydrophobic, semi-crystalline blocks providing domains with well-separated melting temperatures (T(m)s) were synthesized from the same type of precursor building blocks as strictly alternating (MBCsalt) or random (MBCsran) MBCs and compared. Three different series of MBCsalt or MBCsran were synthesized by high-throughput synthesis by coupling oligo(e-caprolactone) (OCL) of different molecular weights (2, 4, and 8 kDa) with oligotetrahydrofuran (OTHF, 2.9 kDa) via Steglich esterification in which the molar ratio of the reaction partners was slightly adjusted. Maximum of weight average molecular weight (M-w) were 65,000 g center dot mol(-1), 165,000 g center dot mol(-1), and 168,000 g center dot mol(-1) for MBCsalt and 80,500 g center dot mol(-1), 100,000 g center dot mol(-1), and 147,600 g center dot mol(-1) for MBCsran. When Mw increased, a decrease of both Tms associated to the melting of the OCL and OTHF domains was observed for all MBCs. T-m (OTHF) of MBCsran was always higher than Tm (OTHF) of MBCsalt, which was attributed to a better phase segregation. In addition, the elongation at break of MBCsalt was almost half as high when compared to MBCsran. In this way this study elucidates role of the block length and sequence structure in MBCs and enables a quantitative discussion of the structure-function relationship when two semi-crystalline block segments are utilized for the design of block copolymers.},
  language  = {en}
}