Star-Shaped Poly (Γ-Caprolactone-b-Ethylene Glycol): Synthesis, Characterization and Aggregation Behavior

2007 ◽  
Vol 342-343 ◽  
pp. 725-728
Author(s):  
Yu Jiang Fan ◽  
Jie Liang ◽  
Guo Ping Chen ◽  
Tetsuya Tateishi ◽  
Zhong Wei Gu ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Block Copolymer ◽  
Ethylene Glycol ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Aggregation Behavior ◽  
Step Process ◽  
Structure Factors ◽  
Aggregation Behaviors ◽  
Linear Block

Linear and Star-shaped PCL-b-PEG copolymers were synthesized through a two step process, including the first step to synthesize the star-shaped PCL through ring-opening polymerization of Γ-caprolactone initiated from multi-functional alcohol under the existence of tin(II) ethylhexanoate [Sn(Oct)2] catalyst, and the following step to couple the obtained star-shaped PCL with PEG segments using bi-functional linker. The structure of the polymers was confirmed by IR, NMR, GPC, et al. The aggregation behaviors of the star-shape copolymers were compared with that of the linear block copolymer with corresponding molecular weight of each arm, and the influences of structure factors were discussed.

Synthesis of α,ω-bis(3-aminopropyldiethoxylsilane) Poly(tri fluoropropylmethyl)siloxanes

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhendong Shi ◽  
Xinling Wang
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Reaction Rate ◽  
Ring Opening Polymerization ◽  
Step Process ◽  
Molecular Weights ◽  
H Nmr ◽  
One Step ◽  
Ft Ir ◽  
High Yields

AbstractHigh molecular weight α,ω-bis(3-aminopropyldiethoxylsilane) poly(tri fluoropropylmethyl)siloxanes (APTFPMS) were prepared via a “one-step” process, based on the ring-opening polymerization of 1,3,5-tris(trifluoropropylmethyl) cyclotrisiloxane (F3) in the presence of water and 3-aminopropyltriethoxysilane (APTES). GPC, FT-IR and 1H NMR confirmed the structure of the polymers. It was found that the amount of APTES had significant influence on the reaction rate and the molecular weights of polymers decreased with the increasing amount of water. It was probably because both water and the amino group of APTES favoured generation of hydroxyl ions, which efficiently initiate the polymerization of F3 to achieve APTFPMS. In order to verify this mechanism, another “two-step” process was also performed: Firstly the α,ω-dihydroxylated poly(trifluoropropylmethyl) siloxanes were synthesized from F3 catalyzed by both diaminoethane and water, then reacted with APTES to achieve APTFPMS. All the syntheses had high yields and the molecular weight of the polymers ranged from 2000 to 25000.

Catalytic Ring-Opening Polymerization of Renewable Macrolactones to High Molecular Weight Polyethylene-like Polymers

2011 ◽  
Vol 44 (11) ◽  
pp. 4301-4305 ◽  
Author(s):  
Inge van der Meulen ◽  
Erik Gubbels ◽  
Saskia Huijser ◽  
Rafaël Sablong ◽  
Cor E. Koning ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Ring Opening ◽  
Ring Opening Polymerization

The synthesis and polymerization behaviour of silicon-bridged [1]- and [2]ferrocenophanes with sterically demanding trimethylsilyl substituents attached to the cyclopentadienyl rings

1995 ◽  
Vol 73 (11) ◽  
pp. 2069-2078 ◽  
Author(s):  
Timothy J. Peckham ◽  
Daniel A. Foucher ◽  
Alan J. Lough ◽  
Ian Manners
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Monoclinic Space Group ◽  
Organometallic Polymers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cyclopentadienyl Ligands ◽  
Sterically Demanding ◽  
High Molecular Weight Poly

The silicon-bridged [1]ferrocenophane Fe(η-C5H3SiMe3)2(SiMe2) (5) was synthesized via the reaction of Li2[Fe(η-C5H3SiMe3)2]•tmeda (tmeda = tetramethylethylenediamine) with Me2SiCl2 in hexanes. The disilane-bridged [2]ferrocenophane Fe(η-C5H3SiMe3)2(Si2Me4) (7) was prepared using a similar route from the disilane ClMe2SiSiMe2Cl. Despite the presence of sterically demanding SiMe3 substituents on the cyclopentadienyl rings, compound 5 was found to undergo thermal ring-opening polymerization at 170 °C to produce very soluble, high molecular weight poly(ferrocenylsilane) 6 with Mw = 1.4 × 105, Mn = 8.4 × 104. However, the [2]ferrocenophane 7 was found to be resistant to thermal ring-opening polymerization even at 350 °C and decomposed above 380 °C. A single-crystal X-ray diffraction study of 7 revealed that the steric interactions between the bulky SiMe3 groups are relieved by a significant twisting of the disilane bridge with respect to the plane defined by the centroids of the cyclopentadienyl ligands and the metal atom. The angle between the planes of the cyclopentadienyl rings in 7 was found to be 5.4(6)°, slightly greater than that in the non-silylated analogue Fe(η-C5H4)2(Si2Me4) (4a) (4.19(2)°), and dramatically less than the corresponding tilt angle of the strained, polymerizable, silicon-bridged [1]ferrocenophane Fe(η-C5H4)2(SiMe2) (1) (20.8(5)°). The length of the Si—Si bond in 7 (2.342(3) Å) was found to be close to the sum of the covalent radii (2.34 Å). Crystals of 7 are monoclinic, space group C2/c, with a = 23.689(3) Å, b = 11.174(1) Å, c = 31.027(3) Å, β = 109.16(1)°, V = 7758(2) Å3, and Z = 12. Keywords: ring-opening polymerization, ferrocenophane, organometallic polymers.

One-pot synthesis of PLA-b-PHEA via sequential ROP and RAFT polymerizations

2017 ◽  
Vol 8 (39) ◽  
pp. 6086-6098 ◽  
Author(s):  
Ilknur Yildirim ◽  
Pelin Sungur ◽  
Anna C. Crecelius-Vitz ◽  
Turgay Yildirim ◽  
Diana Kalden ◽  
...  
Keyword(s):  
Block Copolymer ◽  
Ring Opening ◽  
Raft Polymerization ◽  
Ring Opening Polymerization ◽  
One Pot ◽  
One Pot Synthesis

A block copolymer library of polylactide and poly(2-hydroxyethyl acrylate) was prepared via sequential ring opening polymerization and RAFT polymerization in a one-pot approach.

Biodegradable Polymers Derived from Amino Acids for Biological Applications

2010 ◽  
Vol 76 ◽  
pp. 30-35 ◽  
Author(s):  
Naomi Cohen-Arazi ◽  
Ilanit Hagag ◽  
Michal Kolitz ◽  
Abraham J. Domb ◽  
Jeoshua Katzhendler
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Ring Opening ◽  
Building Blocks ◽  
Ring Opening Polymerization ◽  
Microwave Assisted Synthesis ◽  
Hydroxy Acids ◽  
Natural Amino Acids ◽  
Direct Condensation ◽  
Positively Charged

Optically active α-hydroxy acids derived from amino acids have been synthesized and polymerized into new biodegradable polyesters. The variety of functional side chains enables the design of positively charged, negatively charged, hydrophobic and hydrophilic chiral building blocks or any combination of these constituents. Hydroxy acids of 15 natural amino acids were prepared with retention of configuration using a straightforward and reliable method of diazotization of α-amino acids. Polyesters were synthesized from these hydroxy acids by a number of methods: direct condensation in bulk, microwave assisted synthesis and ring opening polymerization. The molecular weight of the prepared polymers ranges between 2000 to 5000Da for the direct condensation and the microwave methods, whereas the ring opening polymerization results in high molecular weight polymers (20000 to 30000Da). The polymers were analyzed for their optical activity (Circular Dichroism Spectroscopy), thermal properties (DSC), solubility, molecular weight and polydispersity (GPC), and aqueous degradation. These polymers were tested for their compatibility to neuronal cells growth and differentiation.

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