Sequence Distribution and Cumulative Composition of Gradient Latex Particles Synthesized by a Power-Feed Technique

Abstract

Nonuniform latex particles, with a gradient change in composition between molecular chains, were prepared using a power-feed technique. The feed program of the addition process was quantitatively analyzed, and the corresponding equations were derived. A simple dropwise analysis model was established to simulate the sequence distribution and cumulative composition of gradient latex particles based on traditional free radical copolymerization. This model avoided consideration of the detailed kinetic procedure with great uncertainties in an emulsion polymerization. The apparent reactivity ratio of methyl methacrylate (MMA) and n-butyl acrylate (BA) during the emulsion copolymerization process, which was first measured by utilizing K-T, YBR, and other methods, and together with the conversion function, were used as the model parameters. 1 H NMR and 13 C NMR were used to characterize the experimental sequence distribution and cumulative composition to verify the model. The simulation results are in good agreement with the experimental data, and the model shows great tolerance to reactivity ratios calculated by different methods.

Controllable Crystallization Behavior of Nylon-6/66 Copolymers Based on Regulating Sequence Distribution

“…The peaks at 180.80 ppm (peak f 1 ), 180.54 ppm (peak f 2 ), 180.04 ppm (peak f 3 ), and 179.77 ppm (peak f 4 ) are the carbonyl signals of PA6 segments from 5-AB-5 binary combination, PA6 segments from the 5-AB-6 binary combination, PA66 segments from the 4-AB-5 binary combination,, and PA66 segments from the 4-AB-6 binary combination, respectively, , clearly shown in Figure S1 in the Supporting Information. I 5‑AB‑5 , I 5‑AB‑6 , I 4‑AB‑5 , and I 4‑AB‑6 are the corresponding intensities of the f 1 , f 2 , f 3 , and f 4 peaks, respectively. ,, Consequently, the mole fractions F 5‑AB‑5 , F 5‑AB‑6 , F 4‑AB‑5 , and F 4‑AB‑6 of 5-AB-5, 5-AB-6, 4-AB-5, and 4-AB-6 binary combinations are given by eqs –, The corresponding average lengths of four binary combinations ( L 5‑AB‑5 , L 5‑AB‑6 , L 4‑AB‑5 , and L 4‑AB‑6 ) are given by eqs –, The mole fractions of PA6 segments ( F CL ) and PA66 segments ( F HA ) are obtained by eqs and , The mole fraction of co-polyamide bond ε and the degree of randomness χ are obtained by eqs and , The mole fractions of initial feeding of CL ( f CL ) and HA-salt ( f HA ) are obtained by using eqs and according to the weight proportions ( w CL , w HA ) in Table , and the molar conversion ratios of the two monomers ( C CL / C HA ) are further obtained by using eq , Based on Figure S1 in the Supporting Information, the variables above for all samples are summarized in Table .…”

Tailoring Copolymer Properties by Gradual Changes in the Distribution of the Chains Composition Using Semicontinuous Emulsion Polymerization

“…Additionally, the polydispersity index should also be considered if looking for uniform properties in the product [ 28 ], or for easy processing, particularly for high MW polymers [ 29 ]. To improve the synthesis processes, the use of programmed feeding can help to control comonomer addition in FRC [ 30 ] or CRP [ 31 , 32 ].…”

Synthesis and Performance of Novel Fluorinated Acrylate Polymers: Preparation and Reactivity of Short Perfluoroalkyl Group Containing Monomers

“…The Kelen–Tudos procedure was regarded as one widely accepted method to determine the reactivity ratios of monomers. , This technique was used to determine the reactivity ratios of the synthesized fluorinated (meth)­acrylates and BMA in radical solution copolymerization with BuOAc as solvent. There was no precipitation that appeared in the copolymerization process, and the conversions were restricted below 10% to avoid composition drift.…”