Chemistry, Characterization and Processing of IMC Curing Polymers.

Lau, Kreisler S.Y.

doi:10.21236/ada133479

Cited by 5 publications

(4 citation statements)

References 6 publications

(7 reference statements)

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“…Synthesis of cyclopropylidenecyclobutenes 13-15 and -cyclobutanes 16 The synthesis of the cyclopropylidenecyclobutene system with an unsubstituted cyclopropyl ring is to the best of our knowledge unreported. Because of the ready availability of benzocyclobutenone 17, 6 we used it in the exploratory studies described below in Scheme 4.…”

Section: Resultsmentioning

confidence: 99%

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Synthesis and photosensitized oxygenation of cyclopropylidenecyclobutenes

Sharon¹,

Frimer²

2003

Tetrahedron

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Section: Resultsmentioning

confidence: 99%

“…1-Cyclopropylidene-3-n-butyl-2-cyclobutene (13). 3-n-Butyl-2-cyclobutene-1-one 31 (30, 2 g, 16.1 mmol) was reacted with biscyclopropyltitanocene (34) according to the above general procedure yielding cyclopropylidenecyclobutene 13 as a colorless liquid (607 mg, 4.1 mmol, 26% yield).…”

Section: General Procedures For the Preparation Of Cyclopropylidenecycmentioning

confidence: 99%

Synthesis and photosensitized oxygenation of cyclopropylidenecyclobutenes

Sharon¹,

Frimer²

2003

Tetrahedron

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“…An aqueous solution (water, 10 g) containing SDS (0.16 g) and Me-β-CD (0.1 g) were mixed in a 100 mL three-neck flask equipped with a mechanical stirrer and a condenser. Me-β-CD acted as a phase transfer agent needed to transport C 12 SH from the monomer droplets to reaction loci. − The mixture was stirred, purged thoroughly with nitrogen, and then immersed in an 80 °C thermostated oil bath. A buffered initiator solution (KPS, 0.06 g and NaHCO 3 0.06 g in 1 g water) was then injected into the flask, followed by adding the monomer emulsion (1 mL) to form the seeds in situ.…”

Section: Methodsmentioning

confidence: 99%

Monitoring Polymer Diffusion in a Waterborne 2K Polyurethane Formulation Based on an Acrylic Polyol Latex

et al. 2020

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We report experiments based upon fluorescence resonance energy transfer (FRET) measurements designed to examine mixing at the molecular level of the components of a waterborne 2K polyurethane (WB2KPU) formulation. The system consists of an acrylic polyol latex (M n = 4200 g/mol, D̵ = 2, T g ≈ 15 °C) with a uniform hydrodynamic diameter (d h ) ≈ 120 nm plus a water-dispersible polyisocyanate (hmPIC, Basonat HW1000 from BASF). We prepared components labeled with phenanthrene (Phen) as the donor dye or with a dimethylaminobenzophenone (Nben) as the acceptor dye. Dynamic light scattering was used to monitor the size and size distribution of the components in the dispersed phase in solution. This signal was dominated by the polyol nanoparticles, which were much larger than the tiny droplets formed by the hmPIC in water. Experiments were carried out at a mole ratio of NCO/polyol-OH of 1.3. We found that the particle size and narrow size distribution remained unchanged up to 22 h after mixing the polyol with the PIC. FRET experiments were carried out on samples in the dispersed state as well as on films formed from these dispersions. Films formed from a 1:1 mixture of (polyol-Phen + polyol-Nben) showed relatively little energy transfer (Φ ET = 0.19) even after several hours aging at ambient temperature, indicating that little polymer diffusion occurred in these low-molecular-weight latex films. In contrast, films formed from mixtures of (polyol-Phen + polyol-Nben + hmPIC) showed more extensive energy transfer (ET) (Φ ET = 0.51), indicating essentially complete mixing at the molecular level of the polymer molecules in the presence of hmPIC. The key conclusion is that hmPIC is a reactive plasticizer that promotes diffusion in this system on a much faster scale than the cross-linking reaction. This result is confirmed by experiments that examined mixtures of (hmPIC-Phen + polyol-Nben), which also showed essentially molecular scale mixing between these two different components. In this later system, aging at room temperature led to a small decrease in Φ ET over time that was more prominent for films aged at high humidity (75%) than at lower humidity (45%). This result suggests that hydrolysis of NCO groups in the film, leading to polyurea formation, promotes local phase separation accompanied by a net increase in the average separation of Phen and Nben groups in the film.

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“…At first an excess of the desired phenolic pendant was used to assure complete substitution, hut because of the highly activated chloro leaving groups (ortho to a nitro group) it was determined that only a stoichiometric equivalent was required to complete chlorn displacement. The general procedure involves: (1) the generation of a potassium salt (by reaction with potassium methoxide) of the phenolic pendant in DMSO,(2) addition (under nitrogen atmosphere) of the salt to a solution of the dichlorodinitro-biphenyl intermediate, and(3)the maintenance nf reaction conditions until product formation is judged complete by the TLC analysis.…”

mentioning

confidence: 99%