Photocatalyst-Free and Blue Light-Induced RAFT Polymerization of Vinyl Acetate at Ambient Temperature

2015 ◽  
Vol 36 (24) ◽  
pp. 2181-2185 ◽  
Author(s):  
Chunlai Ding ◽  
Caiwei Fan ◽  
Ganquan Jiang ◽  
Xiangqiang Pan ◽  
Zhengbiao Zhang ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Vinyl Acetate ◽  
Blue Light ◽  
Raft Polymerization

RAFT Polymerization of Vinyl Acetate, Styrene and Acrylates UsingN,N-Dithiocarbamates

2009 ◽  
pp. 37-47 ◽  
Author(s):  
Vidyasagar Malepu ◽  
Christy D. Petruczok ◽  
TuTrinh Tran ◽  
Tianxi Zhang ◽  
Mahesh Thopasridharan ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Raft Polymerization

Photoinduced controlled radical polymerization of methyl acrylate and vinyl acetate by xanthate

2018 ◽  
Vol 9 (21) ◽  
pp. 2897-2904 ◽  
Author(s):  
Jiajia Li ◽  
Xiangqiang Pan ◽  
Na Li ◽  
Jian Zhu ◽  
Xiulin Zhu
Keyword(s):  
Block Copolymer ◽  
Radical Polymerization ◽  
Vinyl Acetate ◽  
Methyl Acrylate ◽  
Raft Polymerization ◽  
Controlled Radical Polymerization

A block copolymer of PMA-b-PVAc was successfully synthesized using photo-induced RAFT polymerization with a xanthate.

Synthesis of functionalized poly(vinyl acetate) mediated by alkyne-terminated RAFT agents

RSC Advances ◽  
2015 ◽  
Vol 5 (111) ◽  
pp. 91225-91234 ◽  
Author(s):  
Joana. R. Góis ◽  
Anatoliy V. Popov ◽  
Tamaz Guliashvili ◽  
Arménio C. Serra ◽  
Jorge F. J. Coelho
Keyword(s):  
Vinyl Acetate ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Reversible Addition

Two new xanthates with alkyne functionalities were synthesized for the reversible addition fragmentation chain transfer (RAFT) polymerization of vinyl acetate (VAc).

Visible light induced fast synthesis of protein–polymer conjugates: controllable polymerization and protein activity

2014 ◽  
Vol 50 (49) ◽  
pp. 6506-6508 ◽  
Author(s):  
Xin Li ◽  
Lei Wang ◽  
Gaojian Chen ◽  
David M. Haddleton ◽  
Hong Chen
Keyword(s):  
Visible Light ◽  
Ambient Temperature ◽  
Raft Polymerization ◽  
Protein Activity ◽  
Polymer Conjugates ◽  
Protein Polymer ◽  
Novel Method ◽  
Fast Synthesis

Visible light induced fast and controllable RAFT polymerization from protein as a novel method for preparing protein–polymer conjugates at ambient temperature.

RAFT Polymerization of Monomers with Highly Disparate Reactivities: Use of a Single RAFT Agent and the Synthesis of Poly(styrene-block-vinyl acetate)

2013 ◽  
Vol 66 (12) ◽  
pp. 1564 ◽  
Author(s):  
Lily A. Dayter ◽  
Kate A. Murphy ◽  
Devon A. Shipp
Keyword(s):  
Block Copolymers ◽  
Vinyl Acetate ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Good Control ◽  
Scanning Calorimetry ◽  
Styrene Polymerization ◽  
Reversible Addition ◽  
Raft Agent ◽  
End Group

A single reversible addition–fragmentation chain transfer (RAFT) agent, malonate N,N-diphenyldithiocarbamate (MDP-DTC) is shown to successfully mediate the polymerization of several monomers with greatly differing reactivities in radical/RAFT polymerizations, including both vinyl acetate and styrene. The chain transfer constants (Ctr) for MDP-DTC for both these monomers were evaluated; these were found to be ~2.7 in styrene and ~26 in vinyl acetate, indicating moderate control over styrene polymerization and good control of vinyl acetate polymerization. In particular, the MDP-DTC RAFT agent allowed for the synthesis of block copolymers of these two monomers without the need for protonation/deprotonation switching, as has been previously developed with N-(4-pyridinyl)-N-methyldithiocarbamate RAFT agents, or other end-group transformations. The thermal properties of the block copolymers were studied using differential scanning calorimetry, and those with sufficiently high molecular weight and styrene composition appear to undergo phase separation. Thus, MDP-DTC may be useful for the production of other block copolymers consisting of monomers with highly dissimilar reactivities.

scholarly journals Accurate Determination of Junction Temperature in a GaN-Based Blue Light-Emitting Diode using Nonlinear Voltage-Temperature Relation

2021 ◽  
Author(s):  
Chibuzo Onwukaeme ◽  
Won-Jin Choi ◽  
Han-Youl Ryu
Keyword(s):  
Ambient Temperature ◽  
Blue Light ◽  
Accurate Determination ◽  
Quadratic Function ◽  
Junction Temperature ◽  
Nonlinear Dependence ◽  
Quadratic Model ◽  
Temperature Relation ◽  
Light Emitting

Abstract We investigate the junction temperature measurements for GaN-based blue light emitting diodes (LEDs) using nonlinear dependence of the forward voltage ( V f ) on temperature. Unlike the conventional linear model of the dependence of V f on temperature, the modeling of the temperature dependent V f with a quadratic function showed good agreements with measured data in the temperature range between 20 and 100 o C. Using the proposed quadratic model, the junction temperature and thermal resistance of the measured LED could be accurately determined as the ambient temperature varied. It was observed that the junction temperature increment remained almost unchanged as the ambient temperature increased from 20 to 80 o C, which could be attributed to the interplay between the decrease in series resistance and the increase in non-radiative recombination with increasing temperature. The presented method for accurate determination of the junction temperature is expected to be advantageously employed for the thermal management of high-power LEDs.

scholarly journals Chitosan-Transition Metal Coordination Biopolymer: A Promising Heterogeneous Catalyst for Radical Ion Polymerization of Vinyl Acetate at Ambient Temperature.

2021 ◽  
Author(s):  
Ibraheem Olayiwola Bisiriyu ◽  
Reinout Meijboom
Keyword(s):  
Thermal Analysis ◽  
Transition Metal ◽  
Ambient Temperature ◽  
Vinyl Acetate ◽  
Density Functional ◽  
High Efficiency ◽  
Average Molecular Weight ◽  
Metal Coordination ◽  
Theory Approach ◽  
Order Kinetic

<p>The present study utilized chitosan obtained from crab shell and transition metal salts as precursors to synthesize chitosan-metal coordination biopolymers of Mn(II), Fe(III), Co(II) and Ni(II) [i.e Chit-Mn(II), Chit-Fe(III), Chit-Co(II) and Chit-NI(II) respectively]. The synthesized coordination biopolymers have been characterized using different instrumental techniques such as spectroscopic (UV-visible, FT-IR, XRD, EDS, and ICP-OES), thermal analysis (TGA and DTA), surface analysis (SEM), and hydrogen-temperature programmed reduction (H<sub>2</sub>-TPR) analysis. Spectroscopic studies confirmed the successful incorporation of the metals into the biopolymer matrix. Thermal analysis and H<sub>2</sub>-TPR revealed the reducibility of the Chit-Fe(III) at 120 ℃. While Chit-Fe(III) and Chit-Ni(II) were inactive, Chit-Co(II) and Chit-Mn(II) were found to be active towards vinyl acetate polymerization in the presence of aqueous Na<sub>2</sub>SO<sub>3</sub>. Furthermore, the polyvinyl acetate (PVAc) produced from Chit-Co(II) compared perfectly with a commercial PVAc and was in higher yield than PVAc produced from Chit-Mn(II). The polymerization has been shown to proceed via surface-initiated atom transfer radical polymerization (SI-ATRP), and the viscosity average molecular weight of PVAc produced has been measured as 25, 078. The density functional theory approach has been used to ascertain the coordination orientation of the Chit-Co(II) and explain its high efficiency towards vinyl acetate polymerization. The catalyst reusability test revealed an insignificant loss of activity for the Chit-Co(II) after seven cycles of polymerization. Kinetic studies show that the vinyl acetate polymerization suits the second-order kinetic model at ambient temperature. Thermodynamic studies also revealed that chain initiation is an endothermic process while chain propagation is an exothermic process. The result of this work also suggests an investigation of chitosan-metal coordination biopolymer via low-ppm ATRP approach for possible biomedical application.</p>

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