Thermal, Mechanical, and Surface Properties of Poly(2‐N‐alkyl‐2‐oxazoline)s

Abstract

Thermal, mechanical, and surface properties of a library of poly(2‐oxazoline)s are investigated. These polymers are suitable to study structure/property relationships as their cationic ROP and the relative facile monomer synthesis allow for control over the molecular structure. The number of carbon atoms in the linear side‐chain is systematically varied from methyl to nonyl. Relations between chemical structures, thermal transitions, surface energies, and elastic moduli are discussed. It is shown that the mechanical and thermal properties of the polymers depend on the presence of a crystalline phase in the material. The amorphous polymers reveal a decrease in the reduced moduli along with a decrease in their respective glass transition temperature with increasing length of the side‐chain. magnified image

Design Strategies for Functionalized Poly(2-oxazoline)s and Derived Materials

“…Furthermore, the optimized conditions also confirmed the feasibility in larger-scale syntheses. This study comprised the successful syntheses of the monomers (MeS)MeOx, [134]. The thermal and mechanical properties of these homopolymers could be correlated with the present phases in the material.…”

A strong cationic Brønsted acid, [H(OEt2)2][Al{OC(CF3)3}4], as an efficient initiator for the cationic ring-opening polymerization of 2-alkyl-2-oxazolines

“…48 Regarding the material properties of PtButOx, a decrease of the glass transition temperature (T g ) would be supposed within the row of butyl isomers and in the increase of further carbon atoms in the substituent in 2-alkyl-2-oxazolines. 49 In the case of further methyl-groups in the side-chain an increase is observed from PEtOx (T g $ 59 C) to poly(2-iso-propyl-2-oxazoline) (PiPrOx, T g $ 67 C), and a further increase might be anticipated due to the lower flexibility of the side chain for PtButOx.…”

“…21 With increasing length of the alkyl chain in the side chain of poly-2-alkyl-2-oxazolines, the glass transition temperature (T g ) decreases (e.g., from methyl-to pentyl-oxazoline (DP ¼ 60) the values decrease from 72 to 21 C). 49 The corresponding polymers obtained from 2-n-butyl-and 2-i-butyl-2-oxazoline exhibit T g -values of 23 and 53 C, respectively. 49 In our case, for PtButOx 60 , a T g of 38 C was determined (Fig.…”

“…49 The corresponding polymers obtained from 2-n-butyl-and 2-i-butyl-2-oxazoline exhibit T g -values of 23 and 53 C, respectively. 49 In our case, for PtButOx 60 , a T g of 38 C was determined (Fig. 4A, blue dashed curve, 2 nd heating run), whereas no such transition was observed in the third heating run (red curve).…”

Metal‐Free Cycloaddition of Internal Alkynes and Multifunctional Azides Under Solvent‐Free Conditions

“…For the softer polymers B and C , an open loop protocol was used with the same load, hold, and unload times and indent force range as mentioned above. [ 29 ] All measurements for each sample were performed in a single automated run in less than 6 h using a 6 × 6 array piezo automation. The reduced modulus E r was determined from the unloading response utilizing the analysis method proposed by Oliver and Pharr.…”