Pretreatment of polypropylene films for following technological processes,part 2: The use of low temperature plasma method

The surface of polypropylene (PP) films was activated by RF plasma method with the use different gases: argon, air, water vapor, and acetic acid vapor. Plasma was diagnosed based on spectra emitted by gas plasma using the method of optical emission spectroscopy. The effectiveness of these processing gases during plasma treatment was analyzed. The effects of PP activation were assessed with the use of IR‐ATR absorption spectroscopy, X‐ray photoelectron spectroscopy, atomic force microscopy, and the analysis of the surface free energy components based on liquid contact angle. The activation of PP surface by plasma treatment resulted in the increased energy of PP surface layer to the extent being dependent on the type of processing gases and in the formation of new chemical groups on it. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Study of diffusion and sorption of bis-(2-chloroethyl)sulfide (SM) and bis-(2-chloroethyl)ether (OM) through polypropylene (PP) and biaxial-oriented polypropylene (bopp) films by the FTIR–ATR spectroscopic method

The diffusion of sulfur mustard (SM) and oxygen mustard (OM) in polypropylene (PP) and biaxial-oriented PP (BOPP) was measured using Fourier transform infrared–attenuated total reflectance (FTIR–ATR) spectroscopy, which allows one to study the diffusion of liquid through thin polymer films in situ. The temperature-dependent diffusion coefficients of OM and SM for PP and BOPP are also reported; these are in good agreement with the values obtained by the weight gain method. The activation energy of diffusion is determined by both methods. The polymer–penetrant interaction parameter (K) and transport number (n) are calculated for the system PP/OM and BOPP/OM by weight gain method. The “n” values indicate a Fickian mode of diffusion. © 1996 John Wiley & Sons, Inc.     

Photografted polymeric networks based on N‐isopropylacrylamide: Depth profiling by infrared spectroscopy

The study presents the application of infrared spectroscopy in attenuated reflection geometry with variable angle of incidence (VA‐ATR‐FTIR) in analysis of the in‐depth distribution of several chemical species in photografted layers. Two types of networks based on N‐isopropylacrylamide (NIPA) and one interpenetrated network of NIPA and N,N‐dimethylacrylamide (DMA) were produced by UV‐induced graft polymerization on polypropylene surfaces. The NIPA‐g‐PP samples were obtained in two different UV irradiation conditions: under broad band irradiation and using soft UV light (λ > 300 nm). NIPA‐co‐DMA‐g‐PP has been obtained using λ > 300 nm. VA‐ATR‐FTIR spectroscopy revealed the distribution of NIPA and DMA units across the thickness of the probed layer, according to the network type and photografting conditions. The spectral analysis of NIPA‐g‐PP reveals the influence of irradiation conditions, particularly the UV‐B radiation, on the coupling of monomers. For the NIPA‐co‐DMA‐g‐PP sample, a slight agglomeration of DMA units near the surface has been observed, which is maybe related to the more reactive character of DMA. According to the nonhomogenous distribution of the NIPA and DMA units inside the grafted layer, the surface contribution can be separated from the bulk one. The depth profile of several chemical species has been finally constructed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46048.     

Migration of additives toward the surface during aging of epoxy coating by infrared spectroscopy

This research highlights the application of multi‐angle attenuated total reflection (ATR) infrared (IR) spectroscopy method in investigating the migration of additives from the bulk toward the surface which happens in the epoxy coating. Concentration profiles of additives such as low molecular polyamide 651 (LMPA 651) and 2,4,6 ‐ tris (dimethylaminomethyl) phenol (DMP‐30) were studied. Analysis of the shape of the additives concentration profiles revealed the existence of enrichment region and indicated the migration phenomenon of additives in epoxy coating during natural aging and accelerated aging processes. The changes of the additives concentration determined by the ATR‐IR method were consistent with the results obtained by FTIR analysis and gravimetric analysis. The result shows that the ATR‐IR method is very promising for investigating the surface chemical changes in epoxy coating due to its nondestructive testing, conveniency, and high efficiency. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40051.     

In situ infrared attenuated total reflectance spectroelectrochemical study of lubricant degradation

An attenuated total reflectance (ATR) infrared (IR) cell was designed using a boron-doped silicon wafer as the optically transparent electrode to simultaneously perform ATR-IR spectroscopic and electrochemical impedance measurements. The degradation of industrial lubricants was investigated by monitoring the near-surface concentration of hydrocarbons, detergents and anti-wear additives and the formation of degradation products, while polarizing the cell using electrochemical impedance spectroscopy (EIS). The detergent and the anti-wear agent concentration on and near the silicon surface, based on the IR spectra, and the sum of bulk solution and charge transfer resistance, based on the impedance spectra, were all at a maximum for 30 h drain oil, and then decreased for later drain oils. These results agree with other independent measurements, such as oil viscosity, total acid number (TAN), and total base number (TBN) to indicate that the lubricant is significantly degraded after 30 h in the engine test. These data demonstrate the potential use of the ATR silicon-based electrochemical cell as a monitoring device for lubricant degradation, and as an effective analytical tool capable of studying interfacial kinetics, surface interactions of the additives, and performance of silicon-based spectroelectrochemical devices.     

Mechanical properties,thermal, and crystallization behavior of polypropylene composites reinforced by starch and wasted cotton cloth

In this study, wasted cotton cloth was bonded with soluble starches as an adhesive, then dried, cut into fiber fragments and filled into polypropylene (PP) to achieve resource efficiency. The mechanical, thermal, and crystallization properties of the composites were characterized. The results indicated that with the addition of wasted cotton cloth treated without or with silane coupling agent (RC or TRC), PP composites' tensile strength, impact strength, and flexural strength have been improved. The heat distortion temperatures increased slowly, indicating that wasted cotton cloth filled into PP can be turned back into useful items without degradation of PP composites exhibited. Thus, it is a good avenue for the utilization of an otherwise wasted cotton cloth resource. The crystallization activation energy, nucleation constant, and folding surface free energy of PP were markedly reduced in PP/RC composites and its compatibilized composites. The value of F(T) gradually increased with the increasing relative degree of crystallinity. The addition of wasted cotton cloth could significantly reduce the spherulitic size of PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface analysis of aminated polypropylene films as an adhesion promoter to polycarbonate film

The surface composition of aminated polypropylene films (PP‐g‐NH₂) and their adhesion to polycarbonate (PC) film were evaluated. The detection of amine groups on PP‐g‐NH₂ surfaces was obtained by X‐ray photoelectron spectroscopy (XPS). Contact angle measurements showed a decreased in the polarity on PP‐g‐NH₂ surface The adhesion between laminated films of PP‐g‐NH₂ and PC was evaluated by T‐peel test and optical microscopy. PC deposited on the PP‐g‐NH₂ surfaces was confirmed by FTIR‐ATR and SEM analysis of delaminated films, which is an indicative of an interaction between reactive sites of each polymer. The adhesion performance between PC and PP was improved by using amine modified polypropylene (PP‐g‐NH₂). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Blocked polyisocyanates containing fluorine atoms as crosslinking agents for polyurethane powder coatings

Using alicyclic diisocyanates (HDI, TMDI, IPDI, H₁₂MDI), aliphatic unfluorinated and fluorinated alcohols, dibutyltin dilaurate as well as triethylamine as catalysts, blocked polyisocyanate crosslinkers for powder lacquers were synthesized. The chemical structure of these compounds was characterized by means of IR, ¹H‐NMR, ¹³C‐NMR, and ¹⁹F‐NMR spectroscopy. Their molecular weight distribution parameters were determined by gel permeation chromatography. These blocked polyisocyanates were used for the production of powder lacquer compositions and coatings. The three‐dimensional surface topography and surface chemical structure of the resulting powder lacquers were investigated by means of confocal microscope and ATR FT‐IR. The values of surface roughness parameters were calculated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Gama radiation-induced graft copolymerization of N-p-hydroxyphenylmaleimide onto polypropylene films

Polypropylene (PP) films were grafted with N-p-hydroxyphenylmaleinide using γ-radiation. The effect of both monomer concentration and dose rate on the degree of grafting was measured. Characterization of the grafted PP films included IR spectroscopy, X-ray diffraction, mechanical properties, thermal stability and surface topology and the dyeing characteristics of the grafted films with different dyes were also investigated.     

Surface functionalization of polypropylene by entrapment of polypropylene‐grafted‐poly(ethylene glycol)

A surface functionalization polypropylene was prepared by entrapment a copolymer of polypropylene‐grafted‐poly(ethylene glycol) into polypropylene. The effects of structure of copolymer, contact dies, and content of modifiers were studied. The results of attenuated total reflection infrared spectroscopy(ATR‐FTIR) and contact angle measurements indicated that PP‐g‐PEG could preferably diffuse onto the surface and effectively increase the hydrophilicity of PP. PPw‐g‐PEG with lower PEG contents, lower molecular weight of PPw and PEG had better selective enrichment on the surface of PP blend film. By grafting of PEG‐OH onto the MPP, PP macromolecular surface modifier with better solvent‐resistance than that of PEG can be achieved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Blocked polyisocyanates containing monofunctional polyhedral oligomeric silsesquioxane (POSS) as crosslinking agents for polyurethane powder coatings

Blocked polyisocyanate crosslinkers for powder coatings were synthesized using alicyclic diisocyanates (TMDI and IPDI), formic acid, (methylaminopropyl)hepta(isobutyl)Si₈O₁₂ (POSS), ?-caprolactam, dibutyltin dilaurate as well as triethylamine as catalysts. The chemical structures of these compounds were characterized by means of IR, ¹H NMR and ¹³C NMR spectroscopy. The three-dimensional surface topography and surface chemical structure of the resulting powder coatings were investigated by using confocal microscope and ATR FT-IR. The values of surface roughness parameters were calculated. The surface topography was correlated with the chemical structure of the coatings and macroscopic surface behaviour: surface free energy, abrasion resistance, hardness, adhesion to the steel surface and impact resistance. Thermogravimetric analysis was employed to assess the hardening property of powder coatings and the thermal decomposition processes.     

Surface modification of poly(propylene) by photoinitiators: Improvement of adhesion and wettability

Different benzophenone‐type photoinitiators were photografted onto poly(propylene) (PP). The polymer surfaces were analyzed by means of contact angle measurements, UV spectroscopy, and FTIR‐ATR. The modified samples showed a better wettability and higher surface energies, increasing from 26 mN/m for pure PP to 36 mN/m for the modified samples. The UV spectrum of the modified PP films showed two absorption bands that could be related to the grafted initiator. The effect of irradiation time and photoinitiator concentration was investigated. Different acrylates were grafted efficiently onto the modified polymer surfaces. FTIR‐ATR and contact angle measurements confirmed the presence of the grafted chains. The surface energy of the grafted surfaces of samples increased to 70 mN/m, depending on the type of acrylate used. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 2341–2350, 2004     

Structure of polyethylene after pulse ion beam treatment

Pulse ion beam treatment was employed for polyethylene (PE) surface modification. Ultraviolet, infrared (IR), IR–attenuated total reflection spectroscopy (IR–ATR), and X-ray photoelectron spectroscopy methods, as well as wetting angle measurement, were used for the analysis of PE structural changes. Theoretical calculations and experimental data showed treated PE surfaces to have a layered structure. It was found that the upper layer contains various products of PE oxidation and the lower layer contains products of PE decomposition, that is, condensed aromatic structures. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1071–1077, 1998     

Surface‐enhanced infrared absorption (SEIRA) and its use in analysis of plasma‐modified surface

A thin film (<10 nm) of fine metal clusters (silver or gold) with an island form was deposited on a CaF₂ salt plate by slow vacuum thermal evaporation. Molecular layers of stearic acid, p‐nitrobenzoic acid, and m‐nitrobenzoic acid (p‐ and m‐NBA) were prepared on the thin metal film. The system was then examined by infrared spectroscopy attenuated total reflection (IR–ATR). It was found that through the interaction between the metal islands film and the electric field of the incident IR beam the infrared absorption of the molecule layers adsorbed on the islands was enhanced by a factor of 17. The surface‐enhanced IR absorption (SEIRA) also presents a selection rule. This method was then used to study the surface modification with O₂ and NH₃ plasma and the plasma polymerization of allylamine. This is the first time that SEIRA has been used in plasma investigations. A model is provided to explain the interactions between the metal islands film and the electric field of the incident IR beam in the SEIRA. The in‐plasma‐built functional groups can be further used to graft biofunctional molecules for the biomedical industry. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1231–1237, 1999     

Monitoring Early Hydration of Cement by Ex Situ and In Situ ATR‐FTIR – a Comparative Study

Diffuse Reflection Fourier Transform Infrared (DR‐FTIR) spectroscopy has previously proven to provide time‐resolved insights into early cement hydration spanning ~30 s to ~36 h after completing the mixing. Here, a previously validated ex situ freeze‐dry procedure to stop hydration at preset times is complemented by an in situ Attenuated Total Reflectance (ATR) infrared spectroscopy method. The qualitative overall agreement between ex situ freeze‐drying and in situ monitoring is demonstrated. Moreover, water conversion during hydration comes out clearly in the time‐resolved ATR‐FTIR spectra. This information is absent in DR‐FTIR where buildups of crystal water and hydroxides are observed, while quenching of the hydration process requires removal of free water prior to acquiring the spectra. The ability of the IR technique to monitor the initial rate of hydration as a function of time is validated by comparing to calorimetry. The two approaches are understood to be complementary in that the former monitors alite grain surface hydration, while the latter reflects bulk hydration. IR is complementary to the calorimetry in cases of surface processes in conjunction with low enthalpy changes, that is, initial C–S–H formation and additive related surface chemistry.     

Prompt modification of styrene‐butadiene rubber surface with trichloroisocyanuric acid by increasing chlorination temperature

In this article, the surface of styrene‐butadiene rubber (SBR) was brushed with trichloroisocyanuric acid (TCI) (1 or 2 wt % in ethyl acetate) and then thermally treated under different conditions. The chemical modification was characterized by contact angle measurement and surface energy, ATR‐FTIR spectroscopy, scanning electron microscopy (SEM), and single‐lap shear test. The results revealed that the increase of the chlorination temperature was very effective for SBR surface modification by TCI, leading to enhanced surface wettability and shear strength within several minutes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Surface‐activated nanosilica treated with silane coupling agents/polypropylene composites: Mechanical,morphological, and thermal studies

This work reports the mechanical, morphological, and thermal properties of the polypropylene (PP) nanocomposites containing nanosilica (nano‐SiO₂) which were treated by different functional group silane coupling agents. Four types of silane coupling agents namely aminopropyltriethoxy silane (APTES), glycidyloxypropyltrimethoxy silane (GPTMS), trimethoxysilylpropyl methacrylate (TMPM), and dichlorodimethyl silane (DCMS) were used to modify the surface‐activated nanosilica. To enhance the effectiveness of the coupling, nanosilica was chemically activated and analyzed through FTIR and X‐ray photo electron spectroscopy (XPS). The highest tensile strength was recorded by the activated nanocomposites treated with APTES followed by nanocomposite treated with GPTMS, TMPM, and DCMS, respectively. The addition of silane coupling agents into nano‐SiO₂/PP system further improved the tensile modulus of the PP nanocomposites. From the transmission electron microscopy (TEM) analysis, activated nanosilica treated with APTES showed better nanosilica dispersion in the PP matrix and lesser agglomeration occurred when compared with the other silane coupling agents which were used in this study. Surface activation process does not effectively increase the degree of crystallinity and thermal stability on the PP nanocomposites. However, with the assistance of the surface treatment, it was found that the thermal behavior of the PP nanocomposites had been enhanced. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Structural changes in the surface layer of plastic as a result of sliding friction in a metal-thermoplastic system

Studies on structural changes in the surface layer of plastics during internal sliding friction (friction upon seizing) of metalthermoplastic systems have been carried out. These structural changes were carried out by means of polarized light microscopy, density measurements, X-ray diffraction and IR absorption spectroscopy (ATR). They were carried out for high density polyethylene (HDPE), polypropylene (PP) and nylon 6 (PA6). As a result it was found that the formation of completely different structures was caused by internal sliding friction.     

Surface modification of polyamide nanofiltration membrane by grafting zwitterionic polymers to improve the antifouling property

A simple two‐step surface modification method of polyamide nanofiltration membrane, involving the activation of amide groups by formaldehyde and the subsequent cerium [Ce (IV)]‐induced graft polymerization of zwitterionic 3‐(methacryloylamino) propyl‐dimethyl‐(3‐sulfopropyl) ammonium hydroxide) (MPDSAH) monomers, was employed to improve membrane antifouling property. The membranes before and after modification were characterized by attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR), scanning electron microscopy, and atomic force microscopy. The changes in both surface chemical composition and morphology of membranes confirmed the successful graft polymerizations of MPDSAH onto polyamide nanofiltration membrane. The static water contact angle measurements showed that surface hydrophilicity of the modified membranes was significantly enhanced. As the MPDSAH concentration increased, the water flux of grafted membrane decreased gradually, while salt rejection increased slightly. The fouling experiments with bovine serum albumin solution demonstrated that modified membranes exhibited better resistance to protein fouling. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41144.