Kinetics of radical polymerization—XLV. Steric effects in the radical reactivity of quinones

Simándi, Tatiana L.; Tüdős, F.

doi:10.1016/0014-3057(85)90165-x

Cited by 23 publications

(5 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…So, the pore size in the case of 2,5-DTBQ is ~40 μm ( Figure 4 d), BQ is ~20 μm, DQ is ~65 μm, and NQ is ~30 μm. The pore sizes are in strict accordance with the inhibitory effect of p -quinones [ 51 ]: the shorter the polymer chain of the grafted PMMA ( Scheme 3 ), the shorter the “cross-linking” and the smaller the pore size of the freeze-dried sample. For PMMA synthesized in the presence of the alkylborane– p -quinone system, there is a strict correspondence of the molecular weights of polymers with the inhibitory action of p -quinones [ 47 ].…”

Section: Resultsmentioning

confidence: 75%

“…The amount of unreacted monomer, homopolymer, and the proportion of grafted polymer depends on the structure of p -quinone ( Table 5 ). Thus, in the presence of the weakest inhibitors [ 51 ]—2,5-DTBQ and DQ—the proportion of grafted PMMA is ~40%; a more potent inhibitor, NQ, leads to a copolymer containing 20% PMMA. An increase in the proportion of grafted PMMA and an insignificant amount of homopolymer is present using the most potent inhibitor (BQ) we associate with the course of controlled polymerization characteristic of the alkylborane– p -quinone system [ 47 ].…”

Section: Resultsmentioning

confidence: 99%

“…The higher the rate constant of the reaction of the growth radical with p -quinone, the shorter the chains of the grafted PMMA ( Scheme 3 ) and the lower the molecular weight. The inhibitory effect of quinone decreases in the following order: BQ, NQ, 2,5-DTBQ, and DQ [ 51 ]. In the same sequence, the molecular weight of the grafted PMMA isolated after collagenase hydrolysis increases ( Figure 8 ).…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Scaffold Chemical Model Based on Collagen—Methyl Methacrylate Graft Copolymers

Kuznetsova,

Gushchina,

Lobanova

et al. 2023

Polymers

View full text Add to dashboard Cite

Polymerization of methyl methacrylate (MMA) in aqueous collagen (Col) dispersion was studied in the presence of tributylborane (TBB) and p-quinone: 2,5-di-tert-butyl-p-benzoquinone (2,5-DTBQ), p-benzoquinone (BQ), duroquinone (DQ), and p-naphthoquinone (NQ). It was found that this system leads to the formation of a grafted cross-linked copolymer. The inhibitory effect of p-quinone determines the amount of unreacted monomer, homopolymer, and percentage of grafted poly(methyl methacrylate) (PMMA). The synthesis combines two approaches to form a grafted copolymer with a cross-linked structure—“grafting to” and “grafting from”. The resulting products exhibit biodegradation under the action of enzymes, do not have toxicity, and demonstrate a stimulating effect on cell growth. At the same time, the denaturation of collagen occurring at elevated temperatures does not impair the characteristics of copolymers. These results allow us to present the research as a scaffold chemical model. Comparison of the properties of the obtained copolymers helps to determine the optimal method for the synthesis of scaffold precursors—synthesis of a collagen and poly(methyl methacrylate) copolymer at 60 °C in a 1% acetic acid dispersion of fish collagen with a mass ratio of the components collagen:MMA:TBB:2,5-DTBQ equal to 1:1:0.015:0.25.

show abstract

Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Scaffold Chemical Model Based on Collagen—Methyl Methacrylate Graft Copolymers

Kuznetsova,

Gushchina,

Lobanova

et al. 2023

Polymers

View full text Add to dashboard Cite

show abstract

“…1, curves 2, 2') owing to the inhibiting action of the unchanged quinone and thus to different rates of incorporation of the p-quinone molecules into the polymer chain. The effect is the stronger, the higher is the inhibition constant: for NQ and 2,3-DMBQ, it is 9.75 × 10 3 and 2.33 × 10 4 L mol -1 s -1 [9], respectively. Therefore, for the synthesis of the macroinitiator based on polystryrene, we used the catalytic system containing 0.25 mol % 2,3-DMBQ and NQ in combination with 0.10 mol % AIBN and 0.80 mol % TNBB.…”

Section: Methodsmentioning

confidence: 97%

Tri-n-butylboron-p-quinone catalytic system in synthesis of block copolymers

2015

View full text Add to dashboard Cite

show abstract

“…These are type II photoinitiators. On the other hand, it is well known that quinones are inhibitors of radical polymerization [28][29][30]. This dualism of quinone behavior in photopolymerizing media predetermines the nature of the influence of the quinones not only on the kinetics of the polymerization process, but also on the pore characteristics of the resulting porous polymer.…”

Section: Introductionmentioning

confidence: 99%

Pore Structure Tuning of Poly-EGDMA Biomedical Material by Varying the O-Quinone Photoinitiator

et al. 2023

View full text Add to dashboard Cite

Porous polymer monoliths with thicknesses of 2 and 4 mm were obtained via polymerization of ethylene glycol dimethacrylate (EGDMA) under the influence visible-light irradiation in the presence of a 70 wt% 1-butanol porogenic agent and o-quinone photoinitiators. The o-quinones used were: 3,5-di-tret-butyl-benzoquinone-1,2 (35Q), 3,6-di-tret-butyl-benzoquinone-1,2 (36Q), camphorquinone (CQ), and 9,10-phenanthrenequinone (PQ). Porous monoliths were also synthesized from the same mixture but using 2,2′-azo-bis(iso-butyronitrile) (AIBN) at 100 °C instead o-quinones. According to the results of scanning electron microscopy, all the resulting samples were conglomerates of spherical, polymeric particles with pores between them. Use of mercury porometry showed that the interconnected pore systems of all the polymers were open. The average pore size, Dmod, in such polymers strongly depended on both the nature of the initiator and the method of initiation of polymerization. For polymers obtained in the presence of AIBN, the Dmod value was as low as 0.8 μm. For polymers obtained via photoinitiation in the presence of 36Q, 35Q, CQ, and PQ, the Dmod values were significantly greater, i.e., 9.9, 6.4, 3.6, and 3.7 μm, respectively. The compressive strength and Young’s modulus of the porous monoliths increased symbatically in the series PQ < CQ < 36Q < 35Q < AIBN with decreasing proportions of large pores (over 12 μm) in their polymer structures. The photopolymerization rate of the EGDMA and 1-butanol, 30:70 wt% mixture was maximal for PQ and minimal for 35Q. All polymers tested were non-cytotoxic. Based on the data from MTT testing, it can be noted that the polymers obtained via photoinitiation were characterized by their positive effect on the proliferative activity of human dermal fibroblasts. This makes them promising osteoplastic materials for clinical trials.

show abstract

Kinetics of radical polymerization—XLV. Steric effects in the radical reactivity of quinones

Cited by 23 publications

References 19 publications

Scaffold Chemical Model Based on Collagen—Methyl Methacrylate Graft Copolymers

Scaffold Chemical Model Based on Collagen—Methyl Methacrylate Graft Copolymers

Tri-n-butylboron-p-quinone catalytic system in synthesis of block copolymers

Pore Structure Tuning of Poly-EGDMA Biomedical Material by Varying the O-Quinone Photoinitiator

Contact Info

Product

Resources

About