Fine control of the molecular weight and polymer dispersity <i>via</i> a latent monomeric retarder

Jia, Rui; Tu, Yanyan; Glauber, Mejia; Huang, Zhihao; Xuan, Sunting; Zhang, Weidong; Zhou, Nianchen; Li, Xiaohong; Zhang, Zhengbiao; Zhu, Xiulin

doi:10.1039/d0py01569e

Cited by 18 publications

(20 citation statements)

References 60 publications

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“…Nevertheless, these approaches only tuned the breadth of the MWD and are difficult to tailor the shape of the MWD curve on demand, which is also vital to controlling the properties of polymeric materials. Another method involves tailoring MWD by adjusting external stimuli such as light and heat [33–35] . For example, Chiu exploited a photoisomeric initiator and adjusted photoirradiation times to tune the breadths of MWDs of poly(vinyl ether)s derived from cationic polymerizations [34] .…”

Section: Figurementioning

confidence: 99%

Controlling Polymer Molecular Weight Distribution through a Latent Mediator Strategy with Temporal Programming

Chen

et al. 2021

Angewandte Chemie

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Polymer molecular weight distribution (MWD) is a key parameter of polymers. Here we present a robust method for controlling polymer MWD in controlled cationic polymerizations. A latent mediator strategy was designed and combined with temporal programming to regenerate mediators at different times during polymerization. Both the breadths and shapes of MWD curves were tuned easily by adjusting an external light source. Bimodal, trimodal, and tetramodal distributions were obtained, and the breadths could be varied from 1.06 to 2.09. Polymers with different MWDs prepared by this method had good chain end fidelity, which was demonstrated with successful chain‐extension experiments. In addition, the introduction of temporal programming with a computer‐controlled single chip for the light source opened an avenue for the use of artificial intelligence in polymer synthesis.

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Section: Figurementioning

confidence: 99%

Controlling Polymer Molecular Weight Distribution through a Latent Mediator Strategy with Temporal Programming

Chen

et al. 2021

Angewandte Chemie

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“…Other methods involve the addition of termination agents or co‐monomers to control polymer dispersity, thus leading to partially terminated chains and adulterated polymer chains, respectively. [ 49 , 50 , 51 ]…”

Section: Introductionmentioning

confidence: 99%

Precise Control of Both Dispersity and Molecular Weight Distribution Shape by Polymer Blending

2021

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The breadth and the shape of molecular weight distributions can significantly influence fundamental polymer properties that are critical for various applications. However, current approaches require the extensive synthesis of multiple polymers, are limited in dispersity precision and are typically incapable of simultaneously controlling both the dispersity and the shape of molecular weight distributions. Here we report a simplified approach, whereby on mixing two polymers (one of high Đ and one of low Đ), any intermediate dispersity value can be obtained (e.g. from 1.08 to 1.84). Unrivalled precision is achieved, with dispersity values obtained to even the nearest 0.01 (e.g. 1.37→1.38→1.39→1.40→1.41→1.42→1.43→1.44→1.45), while maintaining fairly monomodal molecular weight distributions. This approach was also employed to control the shape of molecular weight distributions and to obtain diblock copolymers with high dispersity accuracy. The straightforward nature of our methodology alongside its compatibility with a wide range of polymerisation protocols (e.g. ATRP, RAFT), significantly expands the toolbox of tailored polymeric materials and makes them accessible to all researchers.

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“…[42][43][44][45][46][47] Another possibility is to control the broadening of the molecular weight distributions by continuous termination, even though this approach influences the livingness of the resulting polymers. [48][49][50][51][52][53] Lastly, a number of synthetic approaches have recently emerged where dispersity can be controlled by deviating from traditional polymerization recipes. For instance, in reversible complexation mediated polymerization, temperature selectivity is used to achieve good control over the molecular weight distribution: methacrylates are polymerized at mild temperatures (60-70 C), while acrylates require elevated temperatures (110 C).…”

Section: Introductionmentioning

confidence: 99%

Understanding dispersity control in photo‐atom transfer radical polymerization: Effect of degree of polymerization and kinetic evaluation

Rolland

Lohmann

Whitfield

et al. 2021

Journal of Polymer Science

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In photo‐atom transfer radical polymerization (ATRP), dispersity can be efficiently controlled by varying the deactivator concentration. In this work, we provide mechanistic insight into dispersity‐controlled photo‐ATRP by conducting detailed kinetics under a range of conditions. For the lower dispersity polymers, a conventional first‐order kinetic profile was observed accompanied by a linear evolution of number average molecular weight (Mn) with conversion while the reactions reached moderate to high conversions (between 66% and 93%). Whereas, when polymers of high dispersity were targeted, the Mn remained relatively constant throughout the polymerization and the reactions ceased at less than 50% of conversion. In particular, for Ð = 1.84, a significant deviation between theoretical and experimental molecular weights was evident. This deviation was unambiguously attributed to slow initiation as indicated by 1H NMR, where significant percentages of unreacted initiator were observed. Importantly, the addition of ligand at the polymerization plateau re‐initiated the polymerization and led to the complete consumption of the unreacted initiator, thus enabling the synthesis of one‐pot diblock copolymers. We subsequently evaluated the effect of the degree of polymerization (DP) on the obtained dispersity when a constant catalyst ratio was maintained. Based on the interpolation of those experiments results, we could predict experimental conditions for any desirable DPs and dispersities.

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Fine control of the molecular weight and polymer dispersity via a latent monomeric retarder

Abstract: A latent monomeric retarder was used for a one-shot polymerization with a defined MW and Đ.

Cited by 18 publications

References 60 publications

Controlling Polymer Molecular Weight Distribution through a Latent Mediator Strategy with Temporal Programming

Controlling Polymer Molecular Weight Distribution through a Latent Mediator Strategy with Temporal Programming

Precise Control of Both Dispersity and Molecular Weight Distribution Shape by Polymer Blending

Understanding dispersity control in photo‐atom transfer radical polymerization: Effect of degree of polymerization and kinetic evaluation

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