Effect of Composting on the Behavior of Polyolefin Films – A True-to-Life Experiment
Pages 88-100
Viktória Vargha, Tamás Csoknyay, Levente Kárpáti, Gábor Bordós, Mátyás Hartman, Judit Háhn, László Korecz, Györgyi Szarka, Zsolt László, Ottó Kelemen and Sándor Szoboszlay

DOI: http://dx.doi.org/10.6000/1929-5030.2016.05.02.5

Published: 30 May 2016 

Abstract: Commercial polypropylene (PP), high-, medium- and low density polyethylene (HDPE, MDPE, LDPE) films, as well as MDPE films containing pro-oxidative additives and thermoplastic starch (TPS) were composted for six weeks together with biologically degradable films, such as poly (lactic acid) (PLA), Ecovio (BASF), Mater Bi(Novamont) and cellophane. Visual appearance of the polyolefin-based films did not change significantly, while the biologically degradable films fell apart. Thickness and mechanical properties of the polyolefin-based films also did not vary significantly after composting. The thickness of the degradable films however increased due to biofilm formation and finally decreased due to biodegradation, and their mechanical properties drastically dropped. FTIR proved the formation of carbonyl absorption of commercial and of the additive-containing films respectively) after composting due to oxidation. The FTIR-spectrum of the biodegradable films showed drastic change after composting. Formation of free radicals was detectable by ESR-spectroscopy, if pro-oxidative additive containing MDPE film was exposed for one week to sunlight, and the intensity of free radical formation increased after composting. The number-average molecular mass of MDPE films containing pro-oxidative additives decreased, low molecular mass fractions appeared and polydispersity increased after composting. Commercial polyolefin films were covered by microorganisms much more densly than films containing pro-oxidative additives detected by SEM. Even TPS did not increase the quantity of microorganisms. Biodegradable films were densly covered by microorganisms of different types and they became porous and holes were observable on their surface. It can be concluded that composting had no significant effect on the behaviour of the commercial PP and PE films. Signs of initial degradation were observable on MDPE films with pro-oxidative additives and TPS after 6 weeks composting, although it cannot be considered as biological degradation. Non of the tested polyolefin films suffered such degree of degradation in compost, as the biologically degradable films. It may be concluded that polyolefin films neither degrade in compost nor they undergo biodegradation.

Editorial: Special Issue on “Organic/Inorganic Hybrid Materials for Energy and Environment”
Pages 1-2
Takashiro Akitsu

Published: 26 February 2016

Editorial

Recent Advances on Design and Synthesis of Chiral Imidazolium Ionic Liquids and their Applications in Green Asymmetric Synthesis
Pages 3-20
Arijit Saha, Soumen Payra and Subhash Banerjee

DOI: http://dx.doi.org/10.6000/1929-5030.2016.05.01.1

Published: 26 February 2016

Abstract: Over the past decade, catalysis by ionic liquids (ILs) has experienced a tremendous growth in the context of “Green Chemistry”, and there are numerous examples of a variety of catalytic reactions that have been successfully carried out in such neoteric media. The great enthusiasm for catalysis in ILs is not only driven by the curiosity of chemists, but also due to the growing awareness of developing greener reactions or process media in catalytic science and greener catalytic technologies due their advantages of unique physical and chemical properties as compared to traditional volatile organic solvents. Recently, development of chiral ionic liquids and their applications in asymmetric synthesis have attracted much attention as these reactions have widespread applications in the synthesis of chiral drugs and pharmaceutical industries. Asymmetric induction is mainly achieved by the use of chiral substrates or reagents, chiral catalysts or enzymes. Owing to the vast number of structurally different room temperature ILS that have been synthesized, this review focuses on imidazolium ionic liquids that possess chirality either in the imidazolium moiety or in the anion moiety. The aim of this review is to highlight the recent breakthrough of Chiral ILs in chirality transfer or chiral recognition when used as solvent or co-solvent: the case of task specific ionic liquids is beyond the scope of this review. In the first part, the synthesis of of CILs has been presented and the second part of the review has been devoted on the applications of such CILs in green asymmetric synthesis as well as various pharmaceutical industries.

Colloidal Hydroxyapatite/Poly(Acrylic Acid) Hybrids Using Calcium Sucrate and Ammoniumdihydrogen Orthophosphate
Pages 21-29
W.P.S.L. Wijesinghe, M.M.M.G.P.G. Mantilaka, A.M.C.P. Weerasinghe, K.M. Nalin de Silva, T.P. Gamagedara and R.M.G. Rajapakse

DOI: http://dx.doi.org/10.6000/1929-5030.2016.05.01.2

Published: 26 February 2016 

Abstract: This manuscript is concerned with a simple and novel method to synthesize hydroxyapatite-poly(acylic acid) hybrid materials for broad range of applications. In this method, hydroxyapatite nanoparticles are synthesized using calcium sucrate and ammoniumdihydrogen orthophosphate in the presence of poly(acrylic acid). Increase in poly(acrylic acid) concentration in the synthesis medium results in the increase in the hydrodynamic radius of particle size allowing increased hydration. Poly(acylic acid) tends to control both crystallite size and colloidal stability. Increase in poly(acrylic acid) concentration decreases the crystallite size of the products but considerably increases their shelf life as stable colloidal solutions. Thermo gravimetric analysis shows that there are no combustible or volatile impurities present in these samples. This is further supported by FT-IR studies, which show three types of interactions between hydroxyapatite nanoparticles and poly(acrylic acid).

Theoretical Interpretation of Polarized Light-Induced Supramolecular Orientation on the Basis of Normal Mode Analysis of Azobenzene as Hybrid Materials in PMMA with Chiral Schiff Base Ni(II), Cu(II), and Zn(II) Complexes
Pages 30-47
Maiko Ito, Takashiro Akitsu and Mauricio A. Palafox

DOI: http://dx.doi.org/10.6000/1929-5030.2016.05.01.3

Published: 26 February 2016 

Abstract: We have prepared hybrid materials of azobenzene and chiral Schiff base Ni(II), Cu(II), and Zn(II) complexes and investigated their linearly or circularly polarized UV (ultraviolet) light-induced supramolecular orientation with polarized electronic and IR spectra or CD (circular dichroism) spectra. The experimental FT-IR (Fourier transfer-infrared) spectra of azobenzene molecules were recorded at room temperature, and the results were compared with quantum chemical theoretical values using B3LYP, M052X, and M062X DFT (density functional theory) methods. The interaction of azobenzene with PMMA was simulated. Molecular geometry, vibrational wavenumbers, and thermodynamic parameters were calculated in all these systems. With the help of specific scaling procedures for the computed wavenumbers, the experimentally observed FT-IR bands were analyzed and assigned to different normal modes of the molecule. Most modes had wavenumbers in the expected range, and the error obtained was in general very low. Several general conclusions were deduced.