Structure and dynamics in polymer blends: a carbon-13 CPMAS NMR study of poly(3-octylthiophene)/poly(phenylene oxide)

Abstract

We report 13C CPMAS (cross-polarization magic angle spinning) NMR results from meltmixed blends of undoped poly(3-octylthiophene) (POT) and poly(phenylene oxide) (PPO). The behavior of proton spin-lattice relaxation times in the rotating frame (7\P(H)) and laboratory frame (Ti(H)) indicate that the blends are immiscible. Alkyl side-chain 13C spin-lattice relaxation times (7i(C)) increase considerably in blends of POT concentrations lower than ~30%, reflecting an increased molecular flexibility for POT. Changes in mobility are indicated also from dynamic mechanical measurements in which the maximum of the loss tangent for POT is found to shift to lower temperatures in the blends by ~5-15 K. We suggest that the increased mobility is caused by thermal stresses in the material.

A step forward in disclosing the secret of stradivari's varnish by NMR spectroscopy

“…It is well known that T 1ρ H relaxation times are dominated by the spin diffusion phenomenon that, in polymers, tends to average out T 1ρ 's of all protons to a unique value. Despite this, relaxation analysis of heterogeneous systems such as polymeric blends can furnish valuable information …”

“…Despite this, relaxation analysis of heterogeneous systems such as polymeric blends can furnish valuable information. 21 In particular, identical T 1q values for the two components of a blend indicate that polymeric chains are strongly coupled and relax at the same rate because of the spin diffusion mechanism. A blend is then homogenous and the components intimately miscible in a scale of tens of angstroms when the T 1q H values of the two components are equal within the experimental error.…”

Enhanced conductivity in conducting polymer blends induced by aluminum borate whiskers

“…Conducting polymer blends of poly (3-alkylthiophenes) have earlier been examined by several groups [19][20][21][22][23][24].…”

“…In the case of POT blends with whiskers, a continuous structure of the minority POT might be created in spite of the viscosity ratio, e.g. in PE/POT + w. 23 …”

Cross‐Linked Polyamine from Imidazolium‐Based Materials: A Simple Route to Useful Catalytic Materials

“…The proton spin-lattice relaxation times in the rotating frame (T 1ρ H) were obtained to gain information on the protons spin diffusion; that is, the propagation of the magnetization of protons with anti-parallel spins by an energy conserving process. [24] In particular, the higher the number of protons around a carbon nucleus the faster the proton spin diffusion, thus resulting in shorter T 1ρ H values. The T 1ρ H values for all the analyzed materials are reported in Table 1.…”