Study of Ratio Variation of Binary Components of Cross Linking Agent on Extent of Polymerization and Mechanical Properties of Polyurethane Composites

Polyethylene glycol based polyurethane polymer and its fly ash reinforced polyurethane composite were prepared by optimizing the concentration ratio of binders, cross linking agents and curing agents. The components ratio of cross linking agents with the same hydroxyl functionalities i.e. 1,4-butane diol and 1,1,1-trimethylol propane affects the mechanical properties of polymer. The extent of polymerization of polyurethane matrix and fly ash reinforced polyurethane composite was found to be independent of the component ratio of cross linking agents. PEG based polyurethane polymer and their fly ash-reinforced composite can be synthesized at particular ratio by mass of cross linking agents i.e. 0.5 keeping constant w/w ratio 3:2 of binders and curing agents. Effect of w/w ratio variation of cross linking agents on the extent of polymerization has been studied through SEM technique. Cross linking agents, curing agents and polyurethane composite have been characterized by IR spectra. Effect of w/w ratio variation of binary components 1,4-butane diol and 1,1,1-trimethylol propane of cross linking agents on the mechanical properties of fly ash-reinforced polyurethane composite has been studied by evaluating tensile strength and Young modulus of composite material by universal testing machine. Hardness of fly ash-reinforced polyurethane composite with different ratio of 1,4-butane diol and 1,1,1-trimethylol propane of cross linking agents was evaluated by durometer

Fully Biobased Aliphatic Anionic Oligoesters: Synthesis and Properties

Biobased aliphatic sulfonated oligoesters with 10 to 30% of sulfonated units were synthesized by melt polycondensation of biobased monomers such as diethyl succinate, z-octadec-9-enedioic acid, dimer fatty acid, sodium (sulfonated dimethyl succinate), and various diols like 1,4-butane diol and isosorbide. Structural characterization of the resulting oligoesters was determined by 1H NMR spectroscopy and MALDI-TOF MS technique. Showing a regular structure, the nature of the different expected species present in the macromolecular structure allowed the detection of etherification and cyclisation side reactions. The study of the thermal properties indicates that the resulting oligoesters are amorphous or semicrystalline that essentially depend on the nature of monomers. Films of oligoesters treated in acidic, basic, and natural media at 37°C indicate that the remaining weight depends essentially on the composition of oligoesters. Finally, sulfonated oligoester was used to prepare a biobased poly(ester-urethane) thermoset, a material having tunable properties.

The influence of bentonite and montmorillonite addition on thermal decomposition of novel polyurethane/organoclay nanocomposites

Polycarbonate-based polyurethane (PC-PUs) hybrid materials were obtained by the addition oforganically modified bentonite and montmorillonite (1 w/w %). PC-PUs and their nanocomposites wereprepared using prepolymerization with two polycarbonate diols (both of Mr ca 1000) differing in chainconstitution, hexamethylene-diisocyanate and 1,4-butane diol (chain extender) as starting components. All samples contained the same hard-segment content (30 w/w %). Thermogravimetry coupled with differential scanning calorimetry (TG-DSC) was performed to obtain information about the organoclays addition on the thermal stability of the prepared polyurethane elastomers. The effect of bentonite and montmorillonite nanofillers on the decomposition pattern has been evaluated. By deconvolution of derivative thermogravimetric (DTG) curves, it has been found that the thermal decomposition of polyurethane samples takes place in three overlapping processes. Degradation kinetic parameters (activation energy and reaction order) were calculated on the basis of thermal data obtained at only one heating rate.

New Polyurethane Sealants Containing Rosin for Non-Invasive Disc Regeneration Surgery

Different polyurethane sealants were prepared by reacting methylene dyísocyanate and polyadipate of 1,4 butane diol (Mw : 2500 daltons) by using the prepolymer method and different mixtures of rosin and 1,4 butane diol were used as chain extenders. The polyurethanes were characterized by plate-plate rheology, molecular weight distribution, Differential Scanning Calorimetry (DSC), and Laser Confocal Microscopy. The tack of the polyurethanes sealants was obtained by using a modified probe tack method, and their adhesion was obtained by T-peel test of leather/polyurethane sealant/leather joints and by single lap-shear tests of aluminium/polyurethane sealant/aluminium joints. Depending on the rosin content in the chain extender the structure of the polyurethanes was different, i.e. more urethane and urethane-amide hard segments were created up to 50 eq% rosin in the chain extender, and separation of domains was prevailing in the polyurethanes with higher rosin content. Furthermore, the addition of rosin caused an increase in the length of the polymer chains and in the storage modulus (particularly in the polyurethane containing 50 eq% rosin), and decrease in the melting enthalpy. Moreover, the crystallinity of the polyurethanes containing up to 50 eq% rosin showed lower number and smaller spherulites, Finally, the tack at 37 °C and the peel strength increased in the joints made with the polyurethane sealants containing rosin whereas the adhesive shear strength decreased when the polyurethane sealant contained 50 eq% rosin or less.

Synthesis and Properties of New Biodegradable Polyurethane Containing Natural Rubber and Poly(lactic Acid): Effect of NR and PLA Ratio

Biodegradable polyurethane was synthesized using poly(DL-lactic acid) diol and hydroxytelechelic natural rubber as hydroxyl containing precursor, 1,4-butane diol as chain extender, isophorone diisocyanate and dibutyltin dilaurate as catalyst. Poly(DL-lactic acid) diol was prepared by condensation polymerization of DL-lactic acid using 1,4-butane diol as initiator and stannous octoate as catalyst. Hydroxyltelechelic natural rubber synthesized via oxidative degradation of natural rubber and then reduced carbonyl end group to hydroxyl group. Chemical structure of products was characterized by 1H-NMR. Molecular weight and polydispersity determined by SEC. Thermal properties was characterized by DSC and TGA. Segmented polyurethane show two Tgs and two degradation steps corresponding to natural rubber and poly(DL-lactic acid) segment. Polyurethane containing poly(lactic acid) more than 40%mol are become brittle. This result caused by brittle characteristic of PLA. Moreover, mechanical properties increased as content of PLA increased.

The Phase Structure of Novel Polycarbonate-Based Polyurethane-Organoclay Nanocomposites

Polycarbonate-based polyurethane nanocomposites were prepared using one step procedure by addition of either organically modified bentonite or montmorillonite (1 wt. %). All aliphatic components (polycarbonate diol, hexamethylene-diisocyanate and 1,4-butane diol) were used as reactants. The hard segment content of obtained thermoplastic polyurethanes was 30 wt. %. Scanning electron microscopy (SEM) was performed to investigate the morphology of obtained hybrid materials. The structure of synthesized elastomers was studied by Fourier transform infrared spectroscopy (FTIR). In order to obtain the degree of phase separation and investigate the hydrogen bonding constitution, deconvolution of –NH and –C=O IR regions was done, using Gaussian equations. It was determined that the degree of phase separation is not influenced by addition of organoclays, indicating uniform dispersion of silicate layers in the polyurethanes, which was also confirmed by SEM experiments.