Mass spectrometric analysis of polymers derived from
            <i>N</i>
            ‐aryl‐α‐amino acid initiators

Farahani, Masoumeh; Antonucci, Joseph M.; Phinney, Curtis S; Karam, Lisa R.

doi:10.1002/(sici)1097-4628(19970718)65:3<561::aid-app16>3.0.co;2-#

Cited by 8 publications

(13 citation statements)

References 2 publications

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“…2 and 3). Based on the present data and previously reported work [18,19,21], possible routes for the conduct of the spontaneous and photo polymerizations of the HAp-incorporated model self-etch adhesives were proposed in Fig. 7.…”

Section: Discussionmentioning

confidence: 52%

“…Therefore, in order to proceed to the second step, that was, decomposition of the complex to generate the free radicals, involvement of external additives such as HAp was required. This proposed route is distinct from the reported studies [18,19,25] that employed carboxylic acids and NPG (or its analogs). In those systems, the interaction of the carboxylic acids with NPG produced rather unstable complex, probably due to the special chemical structure of NPG that combined both acid and amine groups.…”

Section: Discussionmentioning

confidence: 83%

“…Another effect of the acid–base reaction is associated with possible spontaneous polymerization. Previous studies [17–19] have shown that polymerization of acrylic monomers could be chemically activated with a combination of various carboxylic acids and aromatic amines such as n-phenylglycine (NPG) and n-p-tolylglycine (NTG). The mechanism for the polymerization was speculated to involve the intermediacy of an unstable complex that formed due to the interaction of the carboxylic acid and amine functional groups of the reactants, and subsequent decomposition by an electron transfer process to produce initiating radicals.…”

Section: Introductionmentioning

confidence: 99%

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Hydroxyapatite induces spontaneous polymerization of model self-etch dental adhesives

Zhang

Bai

et al. 2013

Materials Science and Engineering: C

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The objective of this study is to report for the first time the spontaneous polymerization phenomenon of self-etch dental adhesives induced by hydroxylapatite (HAp). Model self-etch adhesives were prepared by using a monomer mixture of bis[2-(methacryloyloxy)ethyl] phosphate (2MP) with 2-hydroxyethyl methacrylate (HEMA). The initiator system consisted of camphorquinone (CQ, 0.022 mmol/g) and ethyl 4-dimethylaminobenzoate (4E, 0.022–0.088 mmol/g). HAp (2–8 wt.%) was added to the neat model adhesive. In a dark environment, the polymerization was monitored in-situ using ATR/FT-IR, and the mechanical properties of the polymerized adhesives were evaluated using nanoindentation technique. Results indicated that spontaneous polymerization was not observed in the absence of HAp. However, as different amounts of HAp were incorporated into the adhesives, spontaneous polymerization was induced. Higher HAp content led to higher degree of conversion (DC), higher rate of polymerization (RP) and shorter induction period (IP). In addition, higher 4E content also elevated DC and RP and reduced IP of the adhesives. Nanoindentation result suggested that the Young's modulus of the polymerized adhesives showed similar dependence on HAp and 4E contents. In summary, interaction with HAp could induce spontaneous polymerization of the model self-etch adhesives. This result provides important information for understanding the initiation mechanism of the self-etch adhesives, and may be of clinical significance to strengthen the adhesive/dentin interface based on the finding.

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Section: Discussionmentioning

confidence: 52%

Section: Discussionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

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Hydroxyapatite induces spontaneous polymerization of model self-etch dental adhesives

Zhang

Bai

et al. 2013

Materials Science and Engineering: C

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“…After repeated experiments to rule out the possibility of accidental light exposure, we turned to the literature to determine if a similar phenomenon had been observed before. Indeed, it was reported decades ago that the spontaneous polymerization of acrylic monomers could be triggered by a combination of carboxylic acids (in our case, the acidic phosphate functional group) and aromatic amines such as n ‐phenyl glycine (NPG; in our case, 4E). The mechanism was uncertain but was speculated to involve the formation of a transient salt or complex between the acid and amine, which is unstable and decomposes into initiating species.…”

Section: Introductionmentioning

confidence: 88%

Ethyl‐4‐(Dimethylamino) benzoate initiation of the spontaneous polymerization of aqueous acidic adhesive formulations in the presence of a base

Bai

Liu

et al. 2013

J of Applied Polymer Sci

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This study indicated that the spontaneous polymerization of an aqueous acidic dental adhesive system containing ethyl-4-(dimethylamino) benzoate (4E) could be activated by various bases. The adhesive was prepared with a monomer mixture of bis[2-(methacryloyloxy)ethyl] phosphate (2MP) and 2-hydroxyethyl methacrylate (HEMA). Various amounts of base [hydroxyapatite (HAP) and its analogues, e.g., Ca(OH) 2 , NaOH, and calcium carbonate] were added. Real-time Fourier transform infrared-attenuated total reflectance spectroscopy was used to monitor the polymerization process. The pH and buffer capacity affected the degree of conversion, and the polymerization rate and induction period were evaluated. The optimal conditions for the pH of this system was between 1.0 and 1.8, and HAP had the best performance on polymerization because of its excellent buffer capacity. The mechanism for the spontaneous polymerization of the 2MP/HEMA adhesive system was proposed with 4E as an initiator.

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“…. [1][2][3] The mechanism(s) for these polymer-Previously, spontaneous polymerization of a variizations appeared to involve the intermediacy of ety of acrylic monomers (e.g., methyl methacryan unstable salt or complex that formed because late and 2-hydroxyethyl methacrylate) was obof the interaction of the carboxylic acid and amine served after activation with a combination of varifunctional groups of the reactants, followed by its ous carboxylic acids (e.g., 2,4-dichlorobenzoic acid decomposition into initiating radicals. 1 The same and trifluoroacetic acid) and aromatic amines type of complex formation and decomposition probably also accounts for the addition of small amounts of radical species derived from N-aryl-a- bonding resins.…”

Section: Introductionmentioning

confidence: 99%

A GC-MS study of the addition reaction of aryl amines with acrylic monomers

Farahani¹,

Antonucci²,

Karam

1998

J. Appl. Polym. Sci.

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ABSTRACT:Previous studies have shown that the interaction of carboxylic acid groups with the amine functionalities of aryl amines, especially secondary and tertiary aryl amines, can lead to the free-radical polymerization of acrylic monomers such as methyl methacrylate. In this study, the Michael addition reaction of primary and secondary aryl amines with acrylic monomers such as acrylic acid (AA) was investigated. Equivalent amounts of either p-toluidine (PT) or N-phenylglycine (NPG) and AA were combined in polar solvents such as ethanol. The reactions were conducted at ambient (23ЊC) or near-ambient (37-60ЊC) temperatures. Samples (about 3-5 mg) of these products were then trimethylsilylated with a solution consisting of 0.4 mL of bis(trimethylsilyl)-trifluoroacetamide (BSTFA) and 0.4 mL of acetonitrile by heating for 30 min at 140ЊC under N 2 . These derivatives were characterized by gas chromatography-mass spectrometry (GC-MS). The GC-MS analyses suggest that 1 mol of the primary amine PT had reacted with 2 mol of AA to yield the expected N-p-tolyliminodipropionic acid. Similarly, the secondary amine NPG added to 1 mol of AA yielded the corresponding mixed iminodiacid, N-phenyliminoacetic-propionic acid. It would appear that the Michael reaction of primary and secondary amines with acrylic monomers may offer a general, facile synthetic route to a variety of tertiary amines. Aryl amino acids of the type synthesized in this study may find use in a number of dental applications, e.g., as surface-active adhesive agents and as polymerization initiators or activators.

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Mass spectrometric analysis of polymers derived from N ‐aryl‐α‐amino acid initiators

Cited by 8 publications

References 2 publications

Hydroxyapatite induces spontaneous polymerization of model self-etch dental adhesives

Hydroxyapatite induces spontaneous polymerization of model self-etch dental adhesives

Ethyl‐4‐(Dimethylamino) benzoate initiation of the spontaneous polymerization of aqueous acidic adhesive formulations in the presence of a base

A GC-MS study of the addition reaction of aryl amines with acrylic monomers

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