Search

This work includes the search for the development of a composite of a WPU (waterborne polyurethane), β-CD (β-Cyclodextrin), PZnO (zinc oxide particles), and the presence of CaCO3, to obtain new properties such as adhesion to multiple substrates of organic and inorganic origin. Therefore, a development sequence was proposed: Computational development: conformation of the polymeric matrix (with the intermediary polymers) and simulation of the interaction between β-CD and PZnO and Ca+2 and CO3-2 ions, as well as insertions in β-CD, computational simulations were carried out with the help of ACD LABS™ (free version) software and by molecular dynamics with GROMACS™. With the above, we were able to determine properties such as interfacial tensions, surface tensions, and contact angles, and degrees of solvation and stability in waterborne emulsions. Therefore, it is important to point out that one of the main contributions of this research proposal is that there are no studies that combine these materials.

The use of Plastics is a very common activity nowadays, there are many different types of Injection Machines varying in size, the capacity of the material to inject, one of the main machines classifications is due to the injection pressure. One of the things to consider when the designing process is carried out is the factor of safety, this factor helps designers to avoid possible failures in mechanical elements of mechanisms, it provides a safety margin that aims to protect against any unexpected incident. The advantage of Simulation is that allows us to predict the behavior of elements under stress. In the Injection Process, barrels are elements subject to high pressure. This encourages analyzing wall thickness to find a suitable barrel wall thickness. The present study is focused on the design of the wall thickness, seeking reduce machining time that are required when producing the barrels that may be needed and to select the proper commercial barrel size reducing material waste.

Magnetic nanoparticles have been used to confer better properties to materials, particularly to polymers. Due the properties of the polymer, such as flexibility and lightness, combined, white nanoparticles provide other properties such as microhardness, corrosion resistance, among others. In this study, three types of nanoparticles were elaborated: magnetite, cobalt ferrite and nickel ferrite, through the coprecipitation method used in the elaboration of skin-like polyurethane (PU) -based composites. Specimens were made at different nanoparticle weights (0.1%, 0.3%, 0.5% and 1.0%). Likewise, the hardness was measured by means of a phase II Model PHT-2500 portable digital hardness tester and the tension tests were carried out on an Autograph Shimadzu universal machine. The stress results were plotted using the Jupyter Notebook for interpretation. Finding some improvements in the materials manufactured using the different ferrites already mentioned.

Metal corrosion affects various sectors: construction, ships, pipes in the chemical industry, etc. Organic materials have been used as coatings to counteract it; recently improvements have been observed when magnetic polymers are used. These are materials formed by a polymeric matrix and a metal with magnetic properties, such as magnetic nanoparticles. The metal is sacrificed, preventing contact with the surface. Here we show the results of composites formed by magnetic nanoparticles of cobalt ferrite and magnetite obtained by coprecipitation, immersed in polystyrene, butyl polyacrylate and styrene-butyl acrylate copolymer matrices. The nanoparticles were incorporated by ultrasonic bath using different weights of nanoparticles (0.05%, 0.25%, 0.5% and 1%) using toluene as solvent. There is an acceptable dispersion of the nanoparticles in the polyacrylate and copolymer after 4 hours of cavitation, the styrene had acceptable dispersion after 5 hours. The composites were tested on a 316 Cal. 14 stainless steel film of 6 cm2 area, the specimens were dipped in acid to evaluate the corrosion protection with electrochemical techniques, having good results in the ferrite and magnetite composites where the protection capacity was better in the styrene-butyl acrylate copolymer.

The objective of the present article is to introduce nanoparticles of a ferromagnetic material (magnetite) to the polymer matrix. We will make some study to verify that the coupling of the nanoparticles in the material was carried out. The present work describes the self-assembly of nanocomposite in suspensión polymerization of PS/PMMA block copolymer, containing magnetite (Fe3O4) which is sonicated with the monomer mixture, with percentages of 0.25% and 0.5% in proportion of the weight of mixture. Photographs were taken with the microscope to verify the coupling of the ferromagnetic material to the polymer matrix, and to verify that couplig, we made characterization by infrared spectroscopy. Also describes the process of nanocomposite synthesis using co-precipitation method, in which ferric chloride and ferrous chloride are combined in an excess basic medium, to subsequently induce the precipitation of the material with a magnet.

Polysiloxanes have been found to be the most important and commercial family of synthetic inorganic polymers. The unique structure of the siloxane bond provides them with unusual features such as a high bond angle, nearly inexistent torsional barrier and a semi-ionic character due to the difference of electronegativities between the silicon and oxygen atoms. Also, silicon-based polymers have been used for the delivery of pharmaceutical and diagnostic compounds involving the use of nanoparticles with different shapes and sizes, as well as hydrogels, including those based on silicon compounds. Hydrogels based on silicon polyolates are rather promising. Some of them exhibit pronounced anti-inflammatory, regenerating, and protective activity, readily penetrate the organism and facilitate drug penetration into the tissues. Due to these properties, polysiloxanes have encountered a big opportunity as an important material in the area of biomedical engineering; the big influence they have in the area of prosthetic dentistry, tissue engineering, cell growth, wounded skin treatments is noteworthy. For the reasons briefly described above, we consider the fact of doing a review about how the polysiloxanes have been used over the years as polymeric matrices that are used in several applications in the field of biomedical engineering.

The creation of films constituted by semiconductor oxides of zinc oxide (ZnO) incorporated into a polar polymer matrix was proposed, looking for such films to be easy to apply, friendly to the environment and compatible with materials. Within the experimental process, the synthesis of styrene copolymers with a polar monomer (methyl methacrylate) was carried out through the suspension and emulsion polymerization processes.

In this research, we focus on the study of the operating conditions that influence on suspension process for obtaining (co)polymers of styrene with polar monomers (copolymers of styrene with acrylate of butyl (S-BA) and copolymers of styrene with vinyl acetate (S-VAc)) using the technique of conventional free radical polymerization (FRP). At higher agitation speed, the reaction performance decreases. Likewise, the influence of the molecular weight of the dispersing agent, in this case polyvinyl alcohol (PVA), influences the polymerization performance was also observed. That is, at a higher molecular weight of PVAs, there is an increase in the particle size of the bead and in the polymerization yield. Finally, there is an influence of the polar part on the copolymer both for the yield and for the particle size of the bead. When obtaining copolymers of S-VAc, the yield is lower compared to the respective styrene homopolymer and higher in the S-BA.

At present, the polymer industry has gained increasing importance due to the versatility of its properties, as well as the impact they have on the environment. The present investigation provides the determination of optimal operating conditions for the polymerization of styrene and vinyl propionate in a Batch reactor, as well as the copolymerization of styrene with propionate monomers by the process of emulsion via free radicals, allowing to observe the variations with respect to Reaction yields and molecular weights. Another important factor is the activation of the initiator so that the polymerization process begins within each of the micelles. Likewise, it was found that, in the copolymerizations, there are considerable variations with respect to reaction yields and molecular weights as the concentrations are modified. In addition, it was found that there are higher yields in styrene polymerizations per solution than emulsion.

The production of artificial polymers is, today, one of themost important activities of the chemical industry, polymersare widely used in everyday life, as, there are different types of polymers, they can be used for different uses. These polymeric materials have unique mechanical, physical and chemical properties, which most other materials do not possess, not to mention that its cost is lower than the other materials. The present research work focuses on the determination of optimal operating conditions for the polymerization of styrene and methyl methacrylate in a Batch reactor, as well as the influence of inorganic salt in this case NaCl in the performance of reaction and in the size of the material polymer, through the process of suspension using a synthetic route of polymerization by radical free conventional (FRP), where viscometry to the polymeric material testing was performed for this way characterize it, and to determine factors of interest such as the molecular weight, etc.

Currently, the polymers industry has gained increasing importance due to the versatility of its properties. In this work were synthesized copolymers of styrene with vinyl acetate at different concentrations through a process polymerization of suspension, which are the starting points for obtaining of composites with polyaniline synthesized PANI chemical oxidative polymerization process, used for doping HCl at a concentration of 1.5 M and ammonium persulfate 0.5 M in a mass radio of 1:1. The conductivity was evaluated by means of cyclic voltammetry and impedance spectroscopy, in order to determine the effect of the concentration of the polar monomer in the composite founded that increase concentration of polar comonomer the conductivity also too.

In the ambit of the synthesis of silicon polymers and elastomers, there are a lot of variables that affect the final properties of the material, and consequently, their applications. In this work, we synthetized polymethylhydrogensiloxane using the ring opening polymerization (ROP) with 2,4,6,8-tetramethylcyclotetrasiloxane as monomer (D4H), a synthetic aluminosilicate like catalytic species and hexamethyldisiloxane as chain blocker. We made a set of experiments, in order to find the effect on the reaction yield, the absence of crosslinking, crosslinking degree and the mechanical properties of the final polymers. We found that the factor “chain blocker addition time” is significant for yield reaction and crosslinking degree of the elastomers, obtaining a greater crosslinking degree and reaction yield when is added at the beginning of the reaction. Also, using DSC measurements, we found an endothermal signal in 553 K corresponding to the elastomer’s chains rearrangement to dissipate the heat supplied. We obtained PMHS chains up to 24,270 g/mol indicating the ability of this kind of catalysts to achieve relatively high molecular weight chains.

Strategies for extracting organic acids from aqueous solutions using polymeric absorbents are demonstrated and discussed in the context of two-phase partitioning bioreactor (TPPB) design. Experimental data and material balances for the uptake of butyric acid and benzoic acid by a poly(ether-block-amide) copolymer (Pebax 2533) establish the inherent limitations of unreactive absorbents for organic acid bioprocesses that operate at near-neutral pH. Improvements to TPPB performance are achieved by lowering pH temporarily with CO2 to enhance acid absorption, and removing the solute-rich polymer before restoring pH to fermentative values by releasing the CO2 pressure. Butyric acid removal by Pebax 2533 improved from 3% to 40% upon acidifying a pH 6 solution with 60 bar of CO2, while benzoic acid absorption increased from 1% to 80% using this pressure manipulation technique. A reactive extraction approach involving a newly-synthesized amine functionalized hydrogel is also described wherein acid/base reaction equilibrium governs the extent of solute uptake. Copolymerization of 2-(dimethylamino)ethyl acrylate (DMAEA) and trimethylolpropane triacrylate (TMPTA) yielded a thermoset material with sufficient basicity to remove 80% of both butyric and benzoic acid from aqueous solution using just 1 wt% polymer relative to the aqueous phase mass.

Pulsed-laser polymerization combined with polymer analysis by NMR and size-exclusion chromatography is used to study the radical copolymerization kinetics of isoprene (IP) with glycidyl methacrylate (GMA). The copolymer is characterized by a close-to-alternating microstructure, with the addition of IP leading to a significant decrease in the composition-averaged propagation rate coefficient. A rigorous fitting strategy is developed to fit a mixed penultimate model to the data, with the selectivity of the IP, but not the GMA, macroradical dependent on the penultimate unit.

Homo and copolymerization of isoprene (IP) with small amounts (1–10 wt %) of glycidyl methacrylate (GMA) are conducted using controlled-living radical polymerization (CRP) mediated by nitroxides (NMP) at 120 °C and 1170 kPa in solution with toluene (30 wt % solids). N-tert-butyl-N-(2-methyl-1-phenylpropyl)-O-(1-phenylethyl) hydroxylamine (TIPAL) is successfully used as a control agent (unimolecular process) although other controllers are also tested (TIPNO and OH-TEMPO in a bimolecular process using BPO as initiator). Chain extension experiments demonstrate the livingness of the synthesized materials. Several additives (acetic anhydride, camphorsulfonic acid and glucose) prove effective in accelerating the reactions. All the successful polymerizations result in first-order kinetics with respect to the monomer, yielding average molecular weights (Mn) of about 75% compared to the theoretical Mn (Mn, theo) with dispersities (Ð) ranging from 1.2 to 1.7 depending on the agent used for control. Controlled grafts of poly (isoprene-co-GMA) are also attached to polyisoprene via nitroxide chemistry. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45108.