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A novel scheme that combines the cross-polarization (CP) with a single-pulse (SP) experiment is developed to quantitatively analyze compositions of multiphase polymers with marked difference in phase mobility. The CPSP method is able to record both CP and SP spectra in one experiment and avoid excessive long relaxation delay, saving considerable experimental time. The quantification of CP spectrum is done by measuring the enhancement factor of CP with a reciprocity relation, while the quantification of SP is derived directly from the Boltzmann distribution in thermo equilibrium. The relative mole composition obtained from a poly(styrene)-poly(isoprene) diblock copolymer matches well with the known value.

We present a new approach to determine quantitatively the phase content of multiphase polymers by applying a spin-diffusion pulse sequence (filter) prior to cross-polarization (CP) in a 13C-CPAS experiment. The technique is exemplified for two rather different polymer systems, a high-density polyethylene (HDPE) and four styrene−isoprene diblock copolymers, all of known phase contents. In principle, the technique should be applicable to any multiphase system in which spin-diffusion between different regions/phases exists and where the magnetization of phases can selectively be filtered out.

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