Search results for "Polymers"

Thermoresponsive hyperbranched polyethylenimines with isobutyramide functional groups

2007

1979

Core‐shell nanoparticles with hyperbranched poly(arylene‐oxindole) interiors

2009

Opracowano synteze wysoce rozgalezionego poli(aryleno-oksyndolu) na drodze reakcji polimeryzacji pochodnej 5-bromoizatyny, a nastepnie modyfikacji terminalnych jednostek izatynowych. Tak przygotowany polimerowy rdzen, charakteryzujący sie stopniem rozgalezienia 100 %, byl substratem do rodnikowej polimeryzacji z przeniesieniem atomu (z ang. ATRP) w reakcji z akrylanem tert-butylu. Otrzymane kopolimery zawierające hydrofobowy rdzen i alkilowe lancuchy zakonczone wolnymi grupami karboksylowymi tworzą sferyczne nanocząstki. Przedstawiono wstepne wyniki badan dotyczących ich wlaściwości fizykochemicznych oraz potencjalnych zastosowan.

Polymerization of styrene

1979

Polyfurfuryl alcohol composite as adsorbent of polychlorinated biphenyls and pyrethroid insecticides

2007

Abstract Composites from furfuryl alcohol and silica gel were prepared in dichloromethane using trifluoroacetic acid as catalyst and characterized by means of thermogravimetric analysis, transmission electron microscopy and nitrogen adsorption–desorption isotherms. The polymer content in the composites ranged between 19.5% and 32.9%. The capability to adsorb polychlorinated biphenyls and pyrethroid insecticides was tested for composite samples containing different percentages of polymer. Pyrethroids are retained almost totally by composites containing around 24–33% of polymer, while recovery of PCBs close to 80% is obtained with all the composites. No selectivity between compounds of the sa…

Bidirectional Chemo-Switching of Spin State in a Microporous Framework

2009

The ins and outs of spin: Using the microporous coordination polymer {Fe(pz)[Pt(CN)(4)]} (1, pz=pyrazine), incorporating spin-crossover subunits, two-directional magnetic chemo-switching is achieved at room temperature. In situ magnetic measurements following guest vapor injection show that most guest molecules transform 1 from the low-spin (LS) state to the high-spin (HS) state, whereas CS(2) uniquely causes the reverse HS-to-LS transition.

Sustainable recycling technologies for thermoplastic polymers and their composites: A review of the state of the art

2022

This review article discusses the environmental and economic effects of recycling, as well as sustainable thermoplastic polymer recycling technologies. Several researchers have utilized recycled thermoplastics as matrices in the production of a variety of natural and synthetic-based composites, which is also the focus of this study. All of the industries (food and packaging, construction and building, transportation, and indoor usage) where recycled thermoplastics have a large market share (food and packaging, construction and building, transportation, and indoor usage) are covered in this review. The desirable properties of thermoplastic polymers, such as corrosion resistance, low density,…

Macro-micro relationship in nanostructured functional composites

2012

This paper examines the results of the characterization of two functional composites: Poly(methyl methacrylate) (PMMA)-Ce:YAG (yttrium aluminium garnet doped with cerium) and PMMA-cobalt hexacyanoferrate (CoHCF). The composites were prepared as possible emitters in the fields of lighting thermal sensors. The prepared composites were char- acterized using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, thermogravi- metric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) analyses to study the correlation between micro and macro characteristics. We found that the molecular interactions of the two different fill…

Behavior of Calcium Phosphate–Chitosan–Collagen Composite Coating on AISI 304 for Orthopedic Applications

2022

Calcium phosphate/chitosan/collagen composite coating on AISI 304 stainless steel was investigated. Coatings were realized by galvanic coupling that occurs without an external power supply because it begins with the coupling between two metals with different standard electrochemical potentials. The process consists of the co-deposition of the three components with the calcium phosphate crystals incorporated into the polymeric composite of chitosan and collagen. Physical-chemical characterizations of the samples were executed to evaluate morphology and chemical composition. Morphological analyses have shown that the surface of the stainless steel is covered by the deposit, which has a very r…

Speciation of organic matter in natural waters. Interaction of polyacrylates with the major cation components of seawater

2004

The speciation of some high molecular weight polycarboxylates was studied in different ionic media. Polyacrylates here investigated (W=2.0, 5.1 and 20.0 kDa) form weak species with alkali metal cations (K=102 mol l1, t=25 jC, I=0 mol l1) and quite stable complexes with alkaline earth metal cations (K>106 mol l1, t=25 jC, I=0 mol l1). Results are reported from experiments performed in a multicomponent electrolyte solution simulating the major composition of seawater (artificial seawater). Protonation constants in this medium are expressed as a polynomial function of S1/2 (S=salinity) and the sharp lowering with respect to values obtained in non-interacting aqueous tetraalkylammonium salts ca…