Radical polymerization of vinyl acetate using p-acetylbenzylidene triphenylarsonium ylide as an initiator

Daniel, Neeta; Srivastava, A. K.

doi:10.1016/s0014-3057(00)00210-x

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…The positive slop indicates an insignificance of PRT. [14][15][16][17] In absence of PRT, considering only DCT, the kinetic data can be analyzed based on a relationship of Deb further simplified by Ghosh and Mitra. [13,15] Again, a positive slope of a plot, for which a negative one was expected in case of DCT, identified no measurable DCT to the initiator.…”

mentioning

confidence: 99%

Non‐Ideal Polymerization Kinetics of a Cationic Double Charged Acryl Monomer and Solution Behavior of the Resulting Polyelectrolytes

Losada

Wandrey

2008

Macromol. Rapid Commun.

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The radical polymerization of bis‐1,3(N,N,N‐trimethylammonium)‐2‐propylmethacrylate dichloride revealed non‐ideality with 0.59 and 4.4 for the reaction orders of the initiator and monomer concentration, respectively. Further, autoacceleration was observed from less than 10% conversion onwards. Degradative chain transfer to the monomer was concluded to explain the initiator exponent. Monomer association and electrostatic effects are hypothesized to govern the monomer exponent and autoacceleration. The exponential concentration dependent increase of the viscosity of the monomer solution and the relatively low overall activation energy Ea = 31.5 kJ · mol−1 support the hypothesis. Counterion activity measurements confirmed strong counterion condensation as expected for a charge distance of 0.12 nm.magnified image

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confidence: 99%

Non‐Ideal Polymerization Kinetics of a Cationic Double Charged Acryl Monomer and Solution Behavior of the Resulting Polyelectrolytes

Losada

Wandrey

2008

Macromol. Rapid Commun.

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“…Ylides are 1,2 dipolar compounds in which a positively charged heteroatom is connected to a carbanion. The search of published research revealed that the ylides containing N, P, As, and Bi have been used as new radical initiator(s) for the polymerization of vinyl monomers like styrene,15 vinyl acetate,16 methyl methacrylate,17, 18 and methyl acrylate 19. The use of stibonium ylide in the domain of polymer science, because of the difficulties associated with their synthesis, is still scarce 20.…”

Section: Introductionmentioning

confidence: 99%

Understanding social obstacles to early breast cancer detection is critical to improving breast cancer outcome in low‐ and middle‐resource countries

Anderson

2010

Cancer

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In most low-and middle-resource countries (LMCs), breast cancer incidence rates are increasing more rapidly than in regions where incidence rates already are high. Despite the younger age structure of most developing countries, LMCs already account for 45% of the incident breast cancer cases and cause 54% of the annual breast cancer deaths around the globe. 1 Even assuming (conservatively) that there will be no change in underlying age-specific rates, a nearly 50% increase is anticipated in breast cancer global incidence and mortality between the years 2002 and 2020 caused simply by the aging of current global populations. These rising cancer rates will be disproportionately greater among countries in the developing world, and the rates in LMCs are projected to reach a 55% increased incidence and a 58% increased mortality in <20 years. 1 In reality, these projected statistics probably underestimate future cancer rates, because the few data available from LMCs reveal increasing age-specific breast cancer incidence and mortality rates, especially among recent birth cohorts. This is especially true for urban women in LMCs and is attributable in part to the adoption of Western lifestyles. 2,3 Improvements in breast cancer survival in the industrialized world that have been observed in recent decades can be attributed to early detection by screening combined with timely and effective treatment as guided by the results of extensive and rigorously performed clinical trials. 4 Randomized trials of screening mammography combined with clinical breast examination (CBE) initiated in the 1970s demonstrated that early cancer detection within a given population leads to down-staging of disease and improvement in breast cancer survival. At the same time, randomized trials of systemic therapies for breast cancer proved that endocrine therapy for estrogen receptor (ER)-positive cancers and cytotoxic chemotherapy for ER-negative cancers improve survival and produce durable long-term cure among patients with lymph node negative, lymph node positive, and even locally advanced breast cancers. 5 Breast cancer mortality essentially was unchanged in the United States for 6 decades between 1930 and 1990. By contrast, since 1990, age-adjusted breast cancer mortality has been dropping by nearly 2% each year in the United States, indicating that true progress is being made in the management of this disease. 6 Similar improvements also are being observed in Western European countries that have invoked population-wide early detection and adjuvant treatment programs.Notably, minority women in the United States are more likely to present with advanced stage disease and have higher mortality rates than white women, although white women and black women who present with similar stage disease and receive similar treatment have similar outcomes. These findings suggest that differences in stage at presentation should represent a primary target for research, the goal of which is to determine which interventions best reduce disparities in cancer outcom...

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“…The search of published research revealed that ylides containing N, P, As or Bi have been used as new radical initiator(s) for the polymerization of vinyl monomers like styrene [5], vinyl acetate [6], methyl methacrylate [7,8] and methyl acrylate [9]. The polymerization of N-vinyl pyrrolidone has been carried out by a number of polymerization techniques like pulsed plasma polymerization [10], radiation graft polymerization [11], bulk polymerization [12], free radical graft polymerization [13] and free radical polymerization [14].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of poly(N-vinyl pyrrolidone) initiated by stibonium ylide

Srivastava¹,

Srivastava²

2006

Designed Monomers and Polymers

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1,2,3,4-Tetraphenylcyclopentadiene triphenyl stibonium ylide initiated radical polymerization of N-vinyl pyrrolidone (N-VP) in dioxane, at 60±0.2 • C, for 60 min under nitrogen atmosphere has been carried out. The system follows ideal kinetics, i.e., R p ∝ [ylide] 0.5 [N-VP] 1.0 . The values of k 2 p /k t and overall energy of activation have been computed as 0.5 × 10 −2 l mol −1 s −1 and 33 kJ/mol, respectively. The FT-IR spectrum shows a band at 1692 cm −1 due to the C O group of N-vinyl pyrrolidone. The 1 H-NMR spectrum shows multiplet at 2.4 δ ppm and a doublet at 3.7 δ ppm due to CH 2 protons. The DSC curve shows a glass transition temperature (T g ) as 48 • C.The presence of six hyperfine lines in the ESR spectrum indicates that the system follows free radical polymerization and the initiation is brought about by phenyl radical.

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Radical polymerization of vinyl acetate using p-acetylbenzylidene triphenylarsonium ylide as an initiator

Cited by 9 publications

References 15 publications

Non‐Ideal Polymerization Kinetics of a Cationic Double Charged Acryl Monomer and Solution Behavior of the Resulting Polyelectrolytes

Non‐Ideal Polymerization Kinetics of a Cationic Double Charged Acryl Monomer and Solution Behavior of the Resulting Polyelectrolytes

Understanding social obstacles to early breast cancer detection is critical to improving breast cancer outcome in low‐ and middle‐resource countries

Synthesis and characterization of poly(N-vinyl pyrrolidone) initiated by stibonium ylide

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