Sub-5 μm balls possessing forest-like poly(methyloxazoline)/polyethyleneimine side chains and templated silica microballs with unusual internal structures

Soma, Daiki; Jin, Ren‐Hua

doi:10.1039/c7ra05329k

Cited by 8 publications

(7 citation statements)

References 54 publications

(47 reference statements)

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“…An efficient initiator leads to a well‐defined polymer with high end‐group functionality. Here, we chose 1,3,5‐tris(bromomethyl) benzene as a trifunctional initiator because the initiator is efficient for the polymerization of 2‐ethyl‐2‐oxazoline and a clean polymerization takes place, and the initiator can be consumed completely . Note that previous studies show that both the electrophilicity and the steric hindrance of initiators can influence the efficiency of the cationic ring‐opening polymerization …”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of degradable hyperbranched poly(2‐ethyl‐2‐oxazoline)

Ali

Cheng

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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Hyperbranched poly(2‐ethyl‐2‐oxazoline) was synthesized by a combination of cationic ring‐opening polymerization and the oxidation of thiol to disulfide groups. A three‐arm star poly(2‐ethyl‐2‐oxazoline) (PEtOx) was first synthesized using 1,3,5‐tris(bromomethyl) benzene as an initiator. The star PEtOx was end‐capped with potassium ethyl xanthate. Similarly, a linear PEtOx was synthesized and end‐capped with potassium ethyl xanthate using benzyl bromide as an initiator. Hyperbranched PEtOx was then obtained by in situ cleaving and subsequent oxidation of the star PEtOx and linear PEtOx mixture with n‐butylamine as both a cleaving agent and a base in tetrahydrofuran. The linear PEtOx was used to prevent the formation of gel. The hyperbranched PEtOx can be cleaved with dithiothreitol to trithiol and monothiol polymer. The hyperbranched PEtOx shows no remaining thiols using Ellman's assay. The resulting hyperbranched PEtOx was hydrolyzed to a novel hyperbranched polyethyleneimine with degradable disulfide linkages. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2030–2037

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Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of degradable hyperbranched poly(2‐ethyl‐2‐oxazoline)

Ali

Cheng

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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“…Our results suggest that both the electrophilic balance and steric hindrance control the efficiency of the initiators for the polymerization of the 2-alkyl-2-oxazoline monomers. Fik et al [34] used a longer bromide initiator with a dodecyl carbon chain and they found that the kinetics and end group functionality along with the dis- tribution were excellent, presumably because the benzene ring between the long carbon chain and the bromide did not affect the electrophilicity of the initiator [36]. Recently, Rasolonjatovo et al [35] used a tetratriflate initiator for the synthesis of poly(THF)-blockpoly(2-methyl-2-oxazoline) and obtained well-defined narrow distributed star polymers.…”

Section: Resultsmentioning

confidence: 99%

A Novel Initiator Containing Alkyne Group for the Polymerization of 2-Ethyl-2-oxazoline

Ali

Gao

Siddiq

et al. 2018

Chinese Journal of Chemical Physics

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A novel trifunctional initiator with one alkyne and two trifluoromethanesulfonate moieties was synthesized from a protected alcohol 5-hydroxyl-2-phenyl-1, 3-dioxane. The alkyne functionalized intermediate with two protected alcohol groups was synthesized by reacting with propargyl bromide. The alcohol groups were cleaved using a mixture of tetrahydrofuran and hydrochloric acid aqueous solution. In the last step the initiator was synthesized using triflic anhydride in carbon tetrachloride. The initiator was characterized by 1 H NMR and used for the polymerization of 2-ethyl-2-oxazoline which gives polymers with narrow distribution. For comparison a similar initiator with two tosylates was prepared and used for the polymerization of the monomer 2-ethyl-2-oxazoline, the resulting product has a wide molecular weight distribution and most of the initiator remains unreacted after 24 h which may be due to the steric hindrance between the two tosylate groups. To further explore the steric hindrance phenomenon, a linear tosylate initiator was synthesized, but still some of the initiator remains unreacted, illustrating that both steric hindrance and electrophilic balance affect the efficiency of the cationic ring-opening polymerization. All of the polymers were characterized in detail by using 1 H NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy, and size exclusion chromatography to confirm the purity and distribution of the polymers.

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“…Polystyrenic microspheres (m-1) were synthesized via a dispersion polymerization process [20][21][22] according to our previous method, 18 as shown in Scheme 1. To a 300 mL three necked round-bottomed ask equipped with a condenser, ethanol (solvent, 150 mL), DMAc (co-solvent, 18 mL), and polyvinylpyrrolidone (PVP K25, 1.8 g) were added, and the mixture was stirred at room temperature (r.t.) until PVP was completely dissolved.…”

Section: Synthesis Of the Poly(p-chloromethylstyrene) Microspheres (M-1)mentioning

confidence: 99%

Theophylline-bearing microspheres with dual features as a coordinative adsorbent and catalytic support for palladium ions

et al. 2018

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Sub-5 μm balls possessing forest-like poly(methyloxazoline)/polyethyleneimine side chains and templated silica microballs with unusual internal structures

Cited by 8 publications

References 54 publications

Synthesis and characterization of degradable hyperbranched poly(2‐ethyl‐2‐oxazoline)

Synthesis and characterization of degradable hyperbranched poly(2‐ethyl‐2‐oxazoline)

A Novel Initiator Containing Alkyne Group for the Polymerization of 2-Ethyl-2-oxazoline

Theophylline-bearing microspheres with dual features as a coordinative adsorbent and catalytic support for palladium ions

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