نتایج جستجو برای: polyesters

تعداد نتایج: 2577  

Journal: :Catalysis Science & Technology 2021

Switchable catalysis is a useful one-pot method to prepare block polyesters utilising single catalyst exposed mixture of monomers.

2017
Izabela Naydenova Ludmila Nikolova Todor Todorov P. S. Ramanujam I. Naydenova

We investigate the polarization properties of holographic gratings in side-chain azobenzene polyesters in which an anisotropic grating that is due to photoinduced linear and circular birefringence is recorded in the volume of the material and a relief grating appears on the surface. A theoretical model is proposed to explain the experimental results, making it possible to understand the influen...

2017
Mahrzadi Noureen Shahi Muhammad Arshad Aman Ullah

Solvent-free copolymerization of epoxides derived from fatty esters of waste cooking oil with phthalic anhydride using (salen)CrIIICl as catalyst and n-Bu₄NCl/DMAP (tetrabutylammonium chloride/4-(dimethylamino)pyridine) as co-catalysts was carried out for the first time under microwave irradiation, where reaction time was reduced from a number of hours to minutes. The polyesters were obtained w...

2010
Malabika Talukdar

Liquid crystal polymers with semiflexible polymer backbone exhibit crystalline order despite of some defects in crystal packing. Isothermal heat treatment of the polymers below and above their liquid crystalline temperatures is expected to provide the necessary energy and time for the molecular chains to overcome the defects in crystal packing and to be arranged in a more perfect crystal lattic...

2017
Zoi Terzopoulou Nejib Kasmi Vasilios Tsanaktsis Nikolaos Doulakas Dimitrios N. Bikiaris Dimitris S. Achilias George Z. Papageorgiou

In the present study, three new biobased furanoate polyesters with potential use in food packaging applications, named poly(isosorbide furanoate) (PIsF), poly(methyl-propylene furanoate) (PMePF) and poly(1,4-cyclohexane-dimethylene 2,5-furanoate) (PCHDMF) were synthesized. As monomers for the preparation of the polyesters, 2,5-furandicarboxylic acid (FDCA) and diols with irregular or complicate...

2017
Chee-Chan Wang Li-Huei Lin Yu-Chun Lo

As people in the 21st century become increasingly environmentally aware, environmentally friendly products have come into focus. As such, environmentally friendly textiles and eco-textiles have become an international trend in research and development. Poly(lactic acid) fiber, which is biodegradable, holds much promise, but it is difficult to deep dye. This study used chitosan, succine anhydrid...

2005
Osamu SATO Mitsumasa Osada Masayuki Shirai Kunio ARAI

Depolymerization behavior polyesters (poly(ethylene terephthalate) (PET) and poly(ethylene 2,6-naphthalene dicarboxylate) (PEN)) in suband supercritical water was investigated for the purpose of monomer recycling. In case of the depolymerization of PET, the yield of terephthalic acid (TPA) increased to 90 % with increasing reaction temperature up to 693 K while the maximum yield of ethylene gly...

Journal: :Molecules 2011
Suhair Saleh Bassam Sweileh Sami O Taha Ruhaifa Mahmoud Mutasem O Taha

Bacterial biofilms constitute an extremely resistant form of bacterial colonization with dire health and economical implications. Towards achieving polymeric composites capable of resisting bacterial adhesion and biofilm formation, we prepared five 2,6-pyridinedicarboxylate-based polyesters employing five different diol monomers. The resulting polyesters were complexed with copper (II) or silve...

2009
Hamid Galehdari Sara Alaee Maisam Mirzaee

The Azotobacter vinelandii is an aerobic, nitrogen-fixing bacterium with the ability to accumulate polyesters such as poly (3-hydroxybutyrate), a particular group of the polyhydroxyalkanoates (pha), when will be cultivated on several carbon sources, including sucrose. Although the capacity of Azotobacter strains to accumulate polyesters is well known, and the genes responsible for their synthes...

2016
Hiep Dinh Nguyen David Löf Søren Hvilsted Anders Egede Daugaard

A one-pot, enzyme-catalyzed bulk polymerization method for direct production of highly branched polyesters has been developed as an alternative to currently used industrial procedures. Bio-based feed components in the form of glycerol, pentaerythritol, azelaic acid, and tall oil fatty acid (TOFA) were polymerized using an immobilized Candida antarctica lipase B (CALB) and the potential for an e...

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