Tomas Lozano-Ramirez

Tecnologico Nacional de Mexico · Departamento de Ingeniería Química

Poly(lactic acid) (PLA) can be functionalized with maleic anhydride (MA) to obtain MA-grafted PLA (PLA-g-MA), which in turn, can be functionalized with ammonium polyphosphate (APP) to obtain PLA-g-APP. This functionalization should facilitate the obtaining of compounds with flame-retardant properties through intumescence and also could function as...

In this work, graphene oxide has been synthesized and functionalized with a silane agent to improve the interactions with nylon 6,6. The functionalization reactions for graphene oxide (GO) resulted in a different way as expected, a heteroatom was grafted into graphene hexagonal network, which led to a new route of chemical modification of graphene...

Polypropylene composites and multi-walled carbon nanotubes (MWCNTs) modified with maleic anhydride (MA) and itaconic anhydride (IA) were prepared and their effect on the performance of nanocomposite properties was studied. Modification of the MWCNT was carried out in the presence of ultrasound varying the molar ratio of anhydride and dicumyl peroxi...

Polycarbonate (PC) was reinforced with pristine and chemically modified graphene oxide (GO) to assess its effect on the PC mechanical properties. Commercial graphene with oxygen contents of 4.7 at %, was used as reference to corroborate the affinity of a GO with oxygen content of 25.6 at. % with PC. GO was modified with 1-ethyl-3-(3-dimethyl aminop...

The effect of ultrasonic (US) irradiation on solutions of low-density polyethylene (LDPE) was studied. Different irradiation times and intensities were examined. It was found that gel content increased very little as a result of US irradiation. However, this increase showed no variation with either the US irradiation time or intensity. The IR spect...

In this work, graphite doped with silver nanoparticles are synthesized and coated onto a PP/EPDM blend surface. Three nanoparticles deposition methods are used. In one method, the nanoparticles are directly deposited on previously corona discharge‐treated TPO surface. Another method is by compression deposition of nanoparticles in a thin layer form...

A study of the improvement of the mechanical and thermal properties of nanocomposites prepared with polypropylene (PP) and different graphene samples [graphene oxide (GO), reduced GO (RGO), and commercial graphene (G)] is presented. X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy characterization were applied to the graphene samples. T...

El azul de metileno se adsorbió sobre la superficie del óxido de grafeno (GO). El óxido de grafeno fue purificado conácido clorhídrico. El potasio (K+) y el manganeso (Mn+2) se eliminaron principalmente durante la purificación. ElGO purificado fue llamado GO aniónico de la misma forma el GO no tratado fue llamado GO catiónico, poseedor ensu mayor p...

The toughness and the rheology of polypropylene (PP)calcium carbonate (CaCO3) nanocompounds using stearic acid as an interface modifier were studied in this work. Compounding of the nanocomposites was carried out with a twin-screwextruder.Thebenchmarksamples(untreated)and stearicacid-treatedCaCO3 nanoparticleswerecharacterized by Fourier transform i...

The toughness and the rheology of polypropylene (PP)‐calcium carbonate (CaCO3) nanocompounds using stearic acid as an interface modifier were studied in this work. Compounding of the nanocomposites was carried out with a twin‐screw extruder. The benchmark samples (untreated) and stearic acid‐treated CaCO3 nanoparticles were characterized by Fourier...

The curing reaction of the epoxy system “diglycidyl ether of bisphenol-A” (DGEBA) and the tertiary amine “2-[(2-dimethyl-amino)-ethoxy] ethanol” (DMAE), with different DMAE concentrations was studied by means of rheometric analysis using the Rubber Process Analyzer (RPA). A novel simple technique was introduced in order to allow the use of the RPA...

Graphene oxide (GO) nanocomposites doped with DEGUSSA (P25) was synthetized by (GO) alcoholic reduction at high temperatures, during the reduction the P25 anchored to the spaces left by carbonyls groups in the graphene network, this incorporation improved photocatalytic behavior by retarding the electro-hole pair (e- h+). Raman spectroscopy confirm...

Polyethylene–montmorillonite nanocomposites were prepared in the melt applying various ultrasonic powers (231, 347, and 462 W) and temperatures (185, 200, and 215 °C) in the presence of itaconic acid. Dispersion–exfoliation of montmorillonite and in situ low density polyethylene functionalization with itaconic acid were carried out by ultrasound as...

In this study, the combination of organomodified montmorillonite (MMT), magnesium hydroxide (MDH), graphene oxide (GO) and expandable graphite (EG) as intumescent flame retardant for Linear Low-Density Polyethylene-Cyclo-Olefin Copolymer (LLDPE/COC) blends has been investigated. An amine-alcohol modified polyethylene (PEgDMAE) was used as compatibi...

The effect of three different organomodified nanoclays (Cloisite 20A, Cloisite 30B, and Nanomer I28E) as well as the effect of a compatibilizer (PEgMA) was studied, with the purpose of developing greenhouse cover films based on polyethylene/ethylene vinyl acetate blends. Three organomodified clays were analyzed. The influence of organomodifier clay...

Maleic anhydride grafted polypropylene (PPgMA) was reacted with aniline (NH2C6H5) to produce PPgNHC6H5 and used as compatibilizer in polypropylene/carbon nanotube composites. Infrared spectroscopy (FTIR) and nuclear-magnetic resonance (NMR) confirmed the reaction between PPgMA and aniline. PPgNHC6H5 resulted a better compatibilizer than PPgMA, prod...

This work presents results of shrinkage and structure characteristics of reinforced PP using combinations of glass fiber and nanoclay with functionalized PP as compatibilizer during injection molding. Shrinkage, warpage and structure characteristics of clay-fiber reinforced nanocomposites using PP grafted with 2-[2- (Dimethylamino) ethoxy] ethanol...

The effect of acrylic acid (AA) and amine alcohol (DMAE) functionalization via plasma of carbon nanofibers (CNF) on physical and mechanical properties of polypropylene-CNF nanocomposites prepared by melt mixing was studied. The behavior of these functionalized CNF via plasma was compared with a CNF functionalized by oxidation with a mixture of sulp...

Processing poly(lactic acid) with low concentrations of silver using a twin-screw extruder leads to nanocomposites with enhanced crystallinity and improved mechanical properties

Poly (L-lactic acid) nanocomposites based on silver nanoparticles (PLA/AgNP) were prepared by melt blending using a twin screw extruder (TSE). Nanocomposites at low concentrations were prepared with 0.1, 0.2 and 0.3wt% of AgNP to enhance the crystallinity and improve the thermal and mechanical properties of PLA. AgNP’s smaller than 100 nm which inc...

Graphene oxide (GO) derived from oxidation of natural graphite contains many active groups that can interact with a great variety of polar moieties. In this work, polypropylene (PP)/graphene oxide nanocomposites using polypropylene (PP) grafted with amine-alcohol (PPgDMAE) as compatibilizer were prepared by two different methods. Maleic anhydride g...

The mechanical properties of polypropylene-bentonite nanocomposites were studied in this work. In this study, stearic acid was used as both a new surface modifier of the nano bentonite and a new interface modifier during the compounding of the nanocomposites with a twin-screw extruder. Three different weight concentrations (1.5 wt.%, 2.5 wt.%, and...

Las propiedades mecánicas de nanocompuestos de polipropileno (PP) con carbonato de calcio (CaCO3) fueron estudiados en este trabajo. Se utilizó ácido esteárico como un nuevo modificador de interfaz durante la preparación de los nanocompuestos utilizando una extrusora de doble husillo. La concentración en peso del nanorelleno (CaCO3) en los compuest...

Abstract Candelilla bagasse fiber (CBF) was prepared by a mesh sieve and ball-milling process and its reinforcing effect in a polymer matrix analyzed. Composites of polypropylene (PP) and CBF were prepared by melt blending with varying amounts (20,25, and 30 wt%) of fiber using maleic anhydride PP as coupling agent. The chemical composition of CBF wa...

A comparative study of the mechanical performance of PP and PP/PP-g-MAH blends reinforced with carbon fibre (CF) obtained by two different moulding techniques is presented. Three filler contents were used for fabricating the composites: 1, 3, and 5 pph (parts per hundred). The crystallisation behaviour of the composites was studied by differential...

In this work, isotactic polypropylene (iPP) nanocomposites were prepared containing silver nanoparticles (Ag-NPs) with a novel and easy method, using polyethylene glycol (PEG) as reducing agent and surface modifier. Ag-NPs were prepared using different amounts in weight of silver nitrate into PEG to induce the formation of Ag-NPs. PP/Ag nano compou...

In this study, we present a study of polypropylene/bentonite composites where stearic acid was used as both a surface and interface modifier during the compounding of composites. The concentration of bentonite was 1.5, 2.5, 5.0, and 10 parts per hundred. The composites were characterized by impact resistance and tensile tests, rheological analysis,...

Las propiedades mecánicas de nanocompuestos de polipropileno (PP) con carbonato de calcio (CaCO3) fueron estudiados en este trabajo. Se utilizó ácido esteárico como un nuevo modificador de interfaz durante la preparación de los nanocompuestos utilizando una extrusora de doble husillo. La concentración en peso del nanorelleno (CaCO3) en los compuest...

In this study, the effect on the degree of organoclay exfoliation in polypropylene-ethylene (PP-EP)/Ethylene vinyl acetate (EVA)/organoclay blend system was studied while varying organoclay structural characteristics. Cloisite 6A, Cloisite 15A, Cloisite 20A, Cloisite 25A, Cloisite 30B, Cloisite 93A, and Cloisite 10A were used because they have diff...

Polypropylene nanocomposite materials were prepared with 5 and 10 wt % cloisite C20A clay, jointly with 0.6 and 1.2 wt % of maleic anhydride (MA) for the simultaneous polymer functionalization and clay dispersion in a twin screw extruder assisted with ultrasonic irradiation, using different sonication intensities (231, 347, and 462 W, which corresp...

The synergistic effect of organo-modified montmorillonite (Nanomer I28E and Cloisite 20A) and metal hydroxides (magnesium hydroxide MH and alumina trihydrate ATH) as flame retardants in LDPE/EVA nanocomposites compatibilized with amino alcohol grafted polyethylene (PEgDMAE) was studied. Morphological characterization of nanocomposites was carried o...

The effects of stearic acid treatment on the crystallization, morphology, thermal, and mechanical properties of polypropylene (PP)/montmorillonite (Mm) nanocomposites were investigated. Stearic acid was used as a new surface modifier for Mm, and also small amounts of this acid were used as a new interface modifier. Nanocomposites containing 1.5, 2....

Hydrogel silver nanocomposites have been used in applications with excellent antibacterial performance. Acrylic acid (AA)/itaconic acid (IA) hydrogels silver nanocomposites were prepared and applied as a coating on a textile substrate. Hydrogel matrices were synthesized first by the polymerization of an AA/IA aqueous (80/20 v/v) solution and mixed...

In this work, we investigated the effect of four different configurations at the exit of a single‐screw extruder on the induction of beta phase in PP for four different rotational speeds. The configuration of a breaker plate with 120 orifices of 1‐mm diameter and 7‐mm length each, give the highest content of beta‐phase (56.92%), for a screw rotatio...

The effects of type of processing of polypropylene (PP)/wollastonite composites on mechanical properties and dispersion state were investigated. The concentration in weight of the filler in the compounds was of 2.5%, 5%, and 10%, respectively. Stearic acid was used as an interface modifier for the PP–wollastonite system. Wollastonite was also modif...

ABSTRACT In this paper, mixtures of polypropylene (PP) are prepared in a single screw extruder using concentrations of filler 5, 10 and 15 parts per hundred of polymer using 3 different types of commercial wollastonite and varying the surface area ratio (L: D) for the binary preparation. One type of modifier compatibilizer polypropylene grafted wi...

The β-phase in polypropylene (PP) induced by shear rate in a single-screw extruder was studied. PP samples were extruded with and without a breaker plate at the exit of the extruder at five different screw rotational speeds: 20, 40, 60, 80, and 100 rpm. Differential scanning calorimeter was used to observe the melting behavior of the samples. The β...

In this paper, a study on Polypropylene (PP)/bentonite composites is presented. PP/bentonite composites were prepared using 5%, 10% and 25% of concentration in weight of unmodified and modified bentonite filler. The relative leve! of the beta phase of the samples was calculated using Wide Angle X-ray Diffraction (WAXD). Differential scanning calori...

Silver nanoparticles were deposited on the surface of the external polyamide 6 (PA6) layer of a multilayer film, by spraying and ultrasound-assisted methods. The effect of silver nanoparticles content and deposition method on the mechanical and optical properties of the multilayered films as well as the efficiency of silver ion release and their fu...

RESUMEN En este trabajo se estudió el comportamiento de las propiedades mecánicas del polipropileno (PP) y el polietileno de baja densidad (PEBD) reciclado después de que ambos fueron reforzados con nanofibra celulósica. Los resultados muestran una disminución de la resistencia al impacto del compósito en comparación con la muestra original. Además...

The compatibilization effects provided by different amines in the synthesis of polypropylene/amine modified montmorillonite clay nanocomposites (PP/ A-MMT) were studied. Nanocomposites were prepared by melt processing using a twin-screw extruder, by compounding maleic anhydride grafted polypropylene (PPgMA) with MMT modified with three different am...

The variations of the cross-linking agent, initiator, and molar ratio in the synthesis of a semi-interpenetrating polymer network (IPN) of polyurethane-starch/polymethyl methacrylate (PMMA) were studied for their viscoelastic and morphologic properties. The synthesized semi-IPNs were evaluated by means of dynamic mechanical analysis (DMA), finding...

It is known that poly(ethylene terephtalate) (PET) and high density poly(ethylene) (HDPE) are very often major contributors to the waste stream, in the form of beverage bottles, films, and so on. Compatibilization between polymer blends is needed to improve the adhesion and to enhance the mechanical properties of both polymers. Some research has em...

A series of ring compression tests were carried out in samples machined from hot- rolled steel slabs to determine the frictional characteristics of various emulsions used for lubrication in cold rolling of steel strip; additional tests were conducted without lubrication or using polytetrafluorethylene (PTFE) tape. The material was tested at differe...

The evaluation of filler dispersion in compounding machines is an important part of their design. Calcium carbonate–filled polypropylene (PP) was used as a model compound to study filler dispersion. The evolution of dispersion was followed in a twin-screw extruder where several types of mixing sections were evaluated. Reverse kneading blocks were f...

Particle size distribution strongly affects physical and mechanical properties of filled polymers. A new model has been developed to predict agglomerate size distribution in a twin-screw extruder (TSE). The model considers the break-up and erosion processes and it uses agglomerate size population balance in its mathematical formulation. The model p...

Particle size distribution affects strongly physical and mechanical properties of filled polymers. The proposed model uses agglomerate size population balance in its new mathematical formulation expressing agglomeration, break-up and erosion as an evolution of one particle subjected to mean-filed type interaction with others. The erosion parameters...

Blends of poly(ethylene terephthalate) (PET) and high-density polyethylene (HDPE) with and without a compatibilizing agent were studied. Both materials are widely used in the soft drink bottle industry. The compatibilizing agent was a copolymer of ethylene and methacrylic acid partially neutralized with zinc (Surlyn). The olefinic segment of Surlyn...