Morphology of Alternating Poly(ester amide)s Based on 1,4-Butylene Established by 13C Solid-State NMR Relaxation Measurements

Abstract

Alternating poly(ester amide)s consisting of 1,4-butylene and diol spacing entities (4NTm and 4NTm,p) were studied using solid-state NMR techniques. The direct monitoring of the NMR relaxation behavior of different ester and amide moieties suggested a significant impact of spacer length on the molecular dynamics. Crystallization domains of the diol spacers of annealed 4NTm as well as 4NTm,p poly(ester amide)s were identified by means of solid-state CP-MAS 13C T1ρ relaxation measurements. From solid-state 1H T1ρ relaxation measurements, the thickness of the lamellae could be estimated including the domain sizes. Quantitative analysis of 13C CP-MAS buildup curves yielded information on the crystallinity of the spacer groups. The macroscopic parameter Tm correlates on a molecular level with (macro)molecular dynamics, thickness of the lamellae, and crystallinity of diol spacers.