Cyclodextrins in Polymer Modification: Diels-Alder Addition of Cyclopentadiene/Methylated-?-Cyclodextrin Complex on Unsaturated Polyester and Formation of a New Type of Polypseudorotaxane

2005 ◽  
Vol 26 (1) ◽  
pp. 40-45 ◽  
Author(s):  
Valentina Alupei ◽  
Iulian C. Alupei ◽  
Helmut Ritter
Keyword(s):  
Unsaturated Polyester ◽  
Diels Alder ◽  
Polymer Modification ◽  
Cyclodextrin Complex ◽  
New Type ◽  
Methylated Cyclodextrin

scholarly journals Enantioselective Diels–Alder reaction of anthracene by chiral tritylium catalysis

2019 ◽  
Vol 15 ◽  
pp. 1304-1312 ◽  
Author(s):  
Qichao Zhang ◽  
Jian Lv ◽  
Sanzhong Luo
Keyword(s):  
Lewis Acid ◽  
Acid Catalyst ◽  
Alder Reaction ◽  
Ion Pair ◽  
Diels Alder ◽  
Highly Active ◽  
Diels Alder Reaction ◽  
New Type ◽  
Lewis Acid Catalyst ◽  
Trityl Cation

The combination of the trityl cation and a chiral weakly coordinating Fe(III)-based bisphosphate anion was used to develop a new type of a highly active carbocation Lewis acid catalyst. The stereocontrol potential of the chiral tritylium ion pair was demonstrated by its application in an enantioselective Diels–Alder reaction of anthracene.

Synthesis and optical properties of tetrapyrazinoporphyrazine containing phenylene dendron unit as a peripheral substituent

2009 ◽  
Vol 13 (08n09) ◽  
pp. 939-948 ◽  
Author(s):  
Chun Keun Jang ◽  
Jae Yun Jaung
Keyword(s):  
Catalytic Properties ◽  
Diels Alder ◽  
Laser Desorption Ionization ◽  
Visible Spectroscopy ◽  
Ionization Time ◽  
H Nmr ◽  
Flight Mass Spectrometry ◽  
Out Of Plane ◽  
New Type ◽  
Uv Visible

A dendritic shell can create a distinct micro-environment within its core. It also has the advantage of possessing unique photochemical, photophysical, electrochemical, and catalytic properties. Polyphenylene dendrons, which are characterized by their shape-persistent structures and out-of-plane twisted phenyl components, have previously been successfully attached to various functional groups. We have recently developed a convenient method for synthesizing a new type of porphyrazine that contains both flexible (linear) and more rigid (dendritic) groups. The synthesis of this completely aromatic and dendronic structure is unique in that it is based on a [2+4] Diels-Alder cycloaddition of tetraphenylcyclopentadienone to an ethynyl compound, followed by the elimination of carbon monoxide. In this study, tetrapyrazinoporphyrazinato metal and metal-free complexes were prepared by mixing 2,3-dicyano-5-polyphenylpyrazines with magnesium in n-butanol. The synthesized tetrapyrazinoporphyrazines were characterized by UV-visible spectroscopy, MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass) spectrometry, elemental analysis and 1 H NMR spectroscopy.

scholarly journals High-Performance Biobased Unsaturated Polyester Nanocomposites with Very Low Loadings of Graphene

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1288 ◽  
Author(s):  
Chengguo Liu ◽  
Cuina Wang ◽  
Jijun Tang ◽  
Jing Zhang ◽  
Qianqian Shang ◽  
...  
Keyword(s):  
High Performance ◽  
Graphene Nanosheets ◽  
Unsaturated Polyester ◽  
Diels Alder ◽  
Mechanical And Thermal Properties ◽  
Comprehensive Properties ◽  
Melt Polycondensation ◽  
Dispersion State ◽  
Structural Plastics

Graphene-reinforced tung oil (TO)-based unsaturated polyester nanocomposites were prepared via in situ melt polycondensation intergrated with Diels–Alder addition. Functionalized graphene sheets derived from graphene oxide (GO) were then extracted from the obtained nanocomposites and carefully characterized. Furthermore, dispersion state of the graphene nanosheets in the cured polymer composites and ultimate properties of the resultant biobased nanocomposites were investigated. Mechanical and thermal properties of the TO-based unsaturated polyester resin (UPR) were greatly improved by the incorporation of GO. For example, at the optimal GO content (only 0.10 wt %), the obtained biobased nanocomposite showed tensile strength and modulus of 43.2 MPa and 2.62 GPa, and Tg of 105.2 °C, which were 159%, 191%, and 49.4% higher than those of the unreinforced UPR/TO resin, respectively. Compared to neat UPR, the biobased UPR nanocomposite with 0.1 wt % of GO even demonstrated superior comprehensive properties (comparable stiffness and Tg, while better toughness and thermal stability). Therefore, the developed biobased UPR nanocomposites are very promising to be applied in structural plastics.

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