Grainy Surface Research Articles

Enhancing thermal stability and corrosion resistance of carbon-carbon composites with iridium coatings deposited by electron beam physical vapor deposition

Abstract Carbon–carbon (C−C) composites are extensively used in high-temperature environments such as Combustor Liners and Turbine Blades in jet engines and Throat Inserts, Nozzle Extensions and Exit Cones in rocket engines due to their excellent thermal stability and mechanical properties. However, at temperatures exceeding 800 °C, these composites require additional protection to prevent degradation. This study aims to investigate the behavior of C−C composites when coated with high-purity metallic iridium using Electron Beam Physical Vapor Deposition (EBPVD). The research problem focuses on enhancing the high-temperature performance and corrosion resistance of C−C composites for aerospace applications. The methodology involves depositing a uniform 5.6 microns thick iridium coating on C−C substrates and characterizing the coating’s microstructure, hardness, and corrosion resistance. FESEM micrographs reveal that the iridium coating adheres uniformly to the substrate without any seepage, and XRD analysis confirms an FCC crystal structure with a densely packed grainy surface. Corrosion tests were conducted using a BIOLOGIC electrochemical workstation in a sodium chloride environment indicate a corrosion rate of 0.00307 mm year−1. The Nyquist, Bodo plots, and Taffel plots were constructed for the better understanding of the corrosion mechanism. While the OCP was constructed to understand the stability and the corrosion resistance of the C−C samples. Microhardness of the coating, measured under a normal applied load of 0.20 N, is 702 HV. The coated samples also could withstand thermal shocks between −40 °C and 1500 °C for 40 h without observable damage or color change. These findings demonstrate the potential of iridium-coated C−C composites to maintain structural integrity and performance in extreme aerospace environments, significantly impacting the field by providing a reliable protective solution for high-temperature applications.

Modification of gamma transmittance at gamma dose absorbed flexible poly (imide siloxane) block copolymer with high thermal performance feature

ABSTRACT Flexible poly (imide siloxane) block copolymer (which was not adhesive feature) was exposed to gamma radiation at 10 kGy by using a certified Co-60 radioisotope for the evaluation of its optimum application condition in gamma irradiation fields with high dose. High gamma dose application has caused to display tuneable high-temperature features as the result of its density development due to radiation hardness effect at 10 kGy. The development of the polysilicon-11 crystallites has caused a decrease in the penetration of gamma photons at the irradiated flexible copolymer due to the gamma absorbed dose. The elimination of the agglomeration by high gamma dose application has assisted the development of the grainy surface at the irradiated flexible copolymer with a more homogeneous structure. The development of the gamma shielding performance of the irradiated polymer has explained the optimum synthesis conditions for the solution of the gamma dose problems at high-temperature applications in contact with the contoured surface (including different heights, depths curvatures on the surface and presenting importance in radiation shielding design and engineering) at high gamma dose areas. A comparison of penetration deepness of gamma photons has indicated its performance (at 0.662 MeV by using the Cs-137 radioisotope and at 1.25 MeV by using the Co-60 radioisotope by using the gamma transmission technique) to determine the details about the density variations of this polymer. The hybrid copolymer was improved to support the development of polymeric instruments for new trend applications in computing and artificial intelligence, biotechnology, and internet of things (for smart monitoring and sensing technology).

Laser Beam Polishing of PA12 Parts Manufactured by Powder Bed Fusion

PurposeMulti Jet Fusion™ (MJF) is a powder bed fusion technology that fuses material locally with infrared radiation. Fabricated parts show high mechanical strength, low porosity and good dimensional accuracy, even for challenging geometries. They do, however, have a distinctive grainy surface with a roughness of Ra > 5 μm limiting possible applications. A fairly recent technology for the smoothing and polishing of polymer surfaces is the surface re-melting by laser beam polishing (LBP). The objective of this study is to characterize the LBP-process of MJF-manufactured Nylon PA12 parts and evaluate it in relation to state-of-the-art finishing methods.MethodsPA12 samples produced using the Multi Jet Fusion™ process are laser beam polished with a 30 W CO2-laser system. A numerical model is applied in order to estimate the effects of different processing parameters and laser scanning strategies. Calculated temperature progressions are validated experimentally with thermographic measurements. The laser beam polished surfaces are subsequently characterised by surface topography, tensile strength, surface energy and hardness.ResultsA re-melting and concurrent smoothing of PA12 surfaces was demonstrated for a number of different processing strategies. The use of a line-focus resulted in the best combination of processing speed, flexibility and surface quality with a reduction in roughness of up to 91%.ConclusionLaser beam polishing is applicable to parts manufactured by Multi Jet Fusion™. Depending on the case of application, it can be preferable to conventional post-processing strategies for fusing residual powder and improving tribological properties.

Investigation of p-type spinel structure as photocathode thin films under neutral pH condition

Owing to the special electronic structure and earth-abundance, spinel structure-based oxides (AB2O4, A = Ni, Cu and B= Co, Fe) have considerable attractive for photo/electro/catalysis. In this work, AB2O4 thin films were synthesized via the spray pyrolysis method on FTO substrates and annealed at 550 °C for 1 h. The structural, morphology, optical and photoelectrochemical properties were studied. The crystalline results show that the thin films have a cubic spinel structure, and the morphology results show a fine grainy surface. The photoelectrochemical measurements in terms of photocurrent density, Incident Photon-to-Current Efficiency (IPCE) and applied bias photon-to-current efficiency (ABPE) were investigated for all samples under neutral pH condition. The results of photocurrent density were (109, 41, 28, 25) μA/cm2 and the IPCE results at 530 nm were 3.05% > 1.52% > 1.42% > 1.32% for CuCo2O4, NiCo2O4, CuFe2O4 and NiFe2O4 respectively under AM 1.5G (100 mW/cm−2) and applied bias −0.5 V. The band structure including the conduction/valence band was determined by Mott-Schottky plot revealing the ability of hydrogen production from neutral water.

Detection of Spread-out Position for Pulse Changing-state of Porous Material-object in Dermis Layer

Grainy surface of moist skin is a stalk transition by grain transport containing monolayer or multilayer multiblock modules as superconductors. Brilliant-differentiation cognition level (BIAL) is conveyed the stiff spread-out-sonance status within the skin to the stalk cognition level function and used a technique of mixing by pulse change. In order to observe the spread-out-sonance status within the skin with the stalk conveyance function, the stalk value with ductile-dot was found and calculated by the superstructure. In the dermis layer, the criterion of brilliant-differentiation level is transition signal by stalk sonance function. Configured as the cognition level and the technical concept of pulse change was measured by the diffusion sonance function that converted into BIAL value by the maximum average. According to the degree of water distribution in the skin, the degree of pulse change was configured as the cognition level of the sonance function, and the value was formed. Stalk ductile-dot sonance presented stalk far transition value of St-CF-FA-?MAX-MED with 11.34±5.57 units. Stalk convenient transition value presented St-CF-CO-?MAX-MED with 2.04±0.51 units. Stalk flank transition value presented St-CF-ST-?MAX-MED with 1.21±0.18 units. Stalk vicinage transition value presented St-CF-VI-?MAX-MED with 0.19±0.11 units. As the degree of ability of the ductile-dot is evaluated spread-out sonance by diffusion function that appeared at the stalk cognition level of the porous material-object by BIAL in the dermis layer. As a differentiation function can be used by the conveyance level system of the dermis layer. Diffusion cognition systems are suppressed by differential signals. Cognition systems is able to exploit the data as promising primary tools for analyzing surfaces from fundamental applications and nanotechnology perspectives.

Sensing Performance of a ZnO-based Ammonia Sensor

Monitoring and remediation of toxic and flammable gases have become a critical task for the development of a clean society. Among various types of metal oxide semiconductors (MOS), zinc oxide (ZnO) is considered a potential material for gas sensing application because of its high sensitivity, easy synthesis, and high thermal stability behaviours. This research aimed to gain an in-depth understanding of the sensing task of a very stable and porous thin film of spin coated ZnO for detecting toxic ammonia vapour at room temperature. As-prepared ZnO films were characterised by x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) analyses. XRD and SEM results revealed the polycrystalline wurtzite ZnO phase with grainy surface morphology. Optical calculations quantify the direct band gap of ZnO as 3.2 eV. The sensitivity measurements showed a good response ratio of 38.5 ± 0.6 with an exposure of 400 ppm of ammonia vapour. The results on sensitivity measurement of several cycles illustrated its stability and sensing performance better than other reported similar works. These findings will be useful to develop a low cost and efficient room temperature MOS gas sensor that can efficiently detect extremely low concentrations as 20 ppm of ammonia vapour which is below the Occupational Safety and Health Administration (OSHA) recommended value.

Sensing Performance of a ZnO-based Ammonia Sensor

Monitoring and remediation of toxic and flammable gases have become a critical task for the development of a clean society. Among various types of metal oxide semiconductors (MOS), zinc oxide (ZnO) is considered a potential material for gas sensing application because of its high sensitivity, easy synthesis, and high thermal stability behaviours. This research aimed to gain an in-depth understanding of the sensing task of a very stable and porous thin film of spin coated ZnO for detecting toxic ammonia vapour at room temperature. As-prepared ZnO films were characterised by x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) analyses. XRD and SEM results revealed the polycrystalline wurtzite ZnO phase with grainy surface morphology. Optical calculations quantify the direct band gap of ZnO as 3.2 eV. The sensitivity measurements showed a good response ratio of 38.5 ± 0.6 with an exposure of 400 ppm of ammonia vapour. The results on sensitivity measurement of several cycles illustrated its stability and sensing performance better than other reported similar works. These findings will be useful to develop a low cost and efficient room temperature MOS gas sensor that can efficiently detect extremely low concentrations as 20 ppm of ammonia vapour which is below the Occupational Safety and Health Administration (OSHA) recommended value.

Characterization of nanoparticulated WO3 electrochromic thin films prepared via precipitation reaction of peroxotungstic acid solution

Amorphous WO3 thin films with a nanoparticulated morphology were fabricated using a combination of electrodeposition and electrophoretic deposition via the precipitation reaction of a peroxotungstic acid (PTA) solution. Due to the presence of the precipitated WO3 nanoparticles in the aged PTA solution, the electrophoretic deposition and electrodeposition occur simultaneously, which results in a grainy surface morphology in which nano-sized WO3 particles are embedded on a smooth WO3 thin film. The WAT-5 sample prepared with a PTA solution aged for 5 days exhibited faster ion intercalation/de-intercalation kinetics (coloration time of 3 s and bleaching time of 1 s), a greater transmittance modulation (68.36%), and a higher coloration efficiency (41.29 cm2/C) with better cyclic stability (91% retention during 300 cycles) than a WO3 thin film fabricated using the PTA solution without the aging process. The nanoparticulated morphology enhanced the active reaction area by expanding the interface between the electrolyte and the electrochromic material. Such results indicate that the electrochromic characteristics of WO3 thin films can be improved simply by adjusting the aging period of the PTA solution.

Unusual Surface Texture, Dimensions and Morphology Variations of Chiral and Single Crystals**

AbstractWe demonstrate here a unique metallo‐organic material where the appearance and the internal crystal structure are in contradiction. The egg‐shaped (ovoid) crystals have a brain‐like texture. Although these micro‐sized crystals are monodispersed; like fingerprints their grainy surfaces are never exactly alike. Remarkably, our X‐ray and electron diffraction studies unexpectedly revealed that these structures are single‐crystals comprising a continuous coordination network of two differently shaped homochiral channels. By using the same building blocks under different reaction conditions, a rare series of crystals have been obtained that are uniquely rounded in their shape. In stark contrast to the brain‐like crystals, these isostructural and monodispersed crystals have a comparatively smooth appearance. The sizes of these crystals vary by several orders of magnitude.

Morphological Effect of Vitamin D Deficiency on Globular Substances in Mice.

Many authors, including us, elucidated that vitamin D deficiency was a risk factor for benign paroxysmal position vertigo. We speculated vitamin D deficiency was likely to intervene otoconia formation by globular substance (GS). Kunming mice were randomly divided into three groups: vitamin D sufficient group (12-wk standard control diet), vitamin D deficiency group (16-wk vitamin D deficiency diet), and vitamin D supplement group (16-wk vitamin D deficiency diet and followed 8-wk standard control diet). At 12, 16, and 24 weeks, blood was collected for measuring vitamin D and macula utriculi were obtained for research under scanning electron microscope (SEM). We randomly selected 10 SEM photographs of macula utriculi in each mouse, counted cilium and GS, and measured diameters of counted GS. The ratio of the number of GS to cilium in each SEM photograph was defined as density of GS. The diameter and density of GS were larger and higher in vitamin D deficiency group than sufficient group (p < 0.05; p < 0.05). There was no significant difference in density and diameters of GS between vitamin D deficiency and supplement group. The rough and grainy surface became smoother and smoother along with vitamin D deficiency, and reappeared after vitamin D supplement for 8 weeks. GS secreted as a precursor of mature otoconia is affected by vitamin D deficiency and vitamin D supplementation can mitigate the effects in mice. The density of GS, a quantitative method we designed, can quantify GS well.

Role of high nitrogen flux in InAlN growth by plasma-assisted molecular beam epitaxy

We study the impact of increased active nitrogen flux (N-flux) on the indium content and structural properties of InAlN layers grown by plasma-assisted molecular beam epitaxy. It is shown that high N-flux can stabilize In-N bonds, so that In0.18Al0.82N is grown at 605 °C, which is the highest reported temperature so far for the composition lattice-matched (LM) to GaN. Adiagram of InAlN indium content is shown as a function of growth temperature and N-flux. The InAlN layers grown using low and high N-flux had grainy surface morphology typical for N-rich conditions. Inhomogeneity in indium distribution on nanometer scale, i.e. typical honeycomb microstructure, is found for InAlN layers grown using both: low and high N-flux. An increase of average cell size is observed for LM-InAlN when the N-flux and growth temperature are increased.

Plasma-assisted molecular beam epitaxy of NiO on GaN(00.1)

The growth of NiO on GaN(00.1) substrates by plasma-assisted molecular beam epitaxy under oxygen-rich conditions was investigated at growth temperatures between 100°C and 850°C. Epitaxial growth of NiO(111) with two rotational domains, with epitaxial relation NiO(11¯0)‖GaN(11.0) and NiO(101¯)‖GaN(11.0), was observed by X-ray diffraction and confirmed by in situ reflection high-energy electron diffraction as well as transmission electron microscopy (TEM) and electron backscatter diffraction. With respect to the high lattice mismatch of 8.1% and a measured low residual tensile layer strain, growth by lattice matching epitaxy or domain-matching epitaxy is discussed. The morphology measured by atomic force microscopy showed a grainy surface, probably arising from the growth by columnar rotational domains visible in TEM micrographs. The domain sizes measured by AFM and TEM increase with the growth temperature, indicating an increasing surface diffusion length. Growth at 850°C, however, involved local decomposition of the GaN substrate that leads to an interfacial β-Ga2O3(2¯01) layer and a high NiO surface roughness. Raman measurements of the quasiforbidden one-phonon peak indicate increasing layer quality (decreasing defect density) with increasing growth temperature.

The Ability of Crystalline and Amorphous Silica from Rice Husk Ash to Perform Quality Hardness for Ceramic Water Filtration Membrane

Silica is an inexhaustible resource on earth. It can be found in food-based natural resources. The natural tendency of silica mainly is to contribute to the strength and the hardness of the ceramic material. This paper investigates the hardness formed in ceramic filtration membrane made by amorphous and crystalline silica from rice husk. Four samples from this material were studied based on unwashed and washed material with chemical, namely, crystalline silica treated with chemical (CS1), crystalline silica untreated with chemical (CS2), amorphous silica treated with chemical (AS1) and amorphous silica untreated with chemical (AS2). To acquire the silica phases, the rice husk was experienced to combustion process at 700oC and 1000oC for 2 hours. The properties of the silica were obtained by using Scanning electron microscopy (SEM) and x-ray diffractometer (XRD) while the value of the hardness was tested by using microhardness tester machine. As a result from SEM both samples of AS1 and AS2 produced an irregular, crinkled, or grainy surface of silica and for sample CS1 and CS2 produced were flushed, unwrinkled and planar surface. For the high hardness value, crystalline silica treated with chemical (CS1) sample was obtained with 171.0.

Stabilizing Solid Electrolyte-Anode Interface in Li-Metal Batteries by Boron Nitride-Based Nanocomposite Coating

Summary Solid-state Li-metal batteries are promising to improve both safety and energy density compared to conventional Li-ion batteries. However, various high-performance and low-cost solid electrolytes are incompatible with Li, which is indispensable for enhancing energy density. Here, we utilize a chemically inert and mechanically robust boron nitride (BN) film as the interfacial protection to preclude the reduction of Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolyte by Li, which is validated by in situ transmission electron microscopy. When combined with ∼1–2 μm PEO polymer electrolyte at the Li/BN interface, Li/Li symmetric cells show a cycle life of over 500 h at 0.3 mA·cm−2. In contrast, the same configuration with bare LATP dies after 81 h. The LiFePO4/LATP/BN/PEO/Li solid-state batteries show high capacity retention of 96.6% after 500 cycles. This study offers a general strategy to protect solid electrolytes that are unstable against Li and opens possibilities for adopting them in solid-state Li-metal batteries.

Surface properties and biocompatibility of thick film materials used in ceramic bioreactors

Low temperature cofired ceramics (LTCC) have conquered a niche segment in biological microelectromechanical systems (BioMEMS) during the last two decades. Since 3-dimensional assembly and rapid prototyping capability are outstanding features of the technology, bioreactors with complex geometry can easily be produced. Particularly needed functions are working electrodes, e.g. for impedance measurements and reference electrodes consisting in platinum or silver-silver chloride. Although the distinct grainy surface of thick film materials influences the double layer properties, data describing the bioelectronic interface and biocompatibility of common thick film materials are rarely published up to now. This works aims to fill this gap by studying the surface properties, composition, electrochemical properties and biocompatibility of commercially available thick film materials. It was found that thick film gold is suitable as electrode material in direct cell contact since an appropriate proliferation of the cell culture was observed. Poly(3,4-ethylenedioxythiophene) coating decreases the absolute value of the zeta potential of thick film gold from 16.55 V to 11.78 mV without any change in vitality of the cells. Thick film platinum layers have a porous structure entailing an enlargement of the effective surface by a factor of 21.6 and can be used as reference instead of silver/silver chloride, which was identified to be incompatible with cell culture. The investigations show that some commercially available cost-effective thick film materials are compatible with cell culture and the here presented data give an orientation for the use of the same in LTCC bioreactors.

Material characterization of thermally evaporated ZnSn2Te4 thin films

Polycrystalline and stoichiometric ZnSn2Te4 (ZST) thin films were deposited on glass substrates by sequential evaporation of elemental powder sources. The deposited films were annealed in nitrogen atmosphere at annealing temperature ranging 100–300 °C. Under post-annealing treatments, the composition, structural, surface morphological, optical and electrical characteristics of the films were investigated. Annealing treatments lead to maintain the structural characteristics with the possible change in atomic concentration of the constituent elements in limit of detection and crystallinity of the films increased with increasing annealing temperature. Grainy surface morphology was observed in as-grown and annealed films and densely packed appearance of the surface of the samples indicates uniform deposition of the film over the entire substrate surface. Under the aim of visible light harvesting in the applications of thin film photovoltaics, normal-incidence transmittance measurements were performed and the direct band gap values were found in the range of 1.8–2.1 eV. Temperature dependent conductivity characteristics of the films were investigated under dark condition and the observed conductivity profiles were found in Arrhenius behavior with temperature dominated by the thermionic emission model.

Intraoral scanner and stereographic 3D print in dentistry—quality and accuracy of model—new laser application in clinical practice

3D print techniques in dentistry have started to become an everyday part of clinical practice. The aim of our study was 3D objectification of stereolithography system (SLA) printed models, including surface analysis. Our investigated group consisted of 50 scans of upper dental arches of medical students obtained by 3Shape TRIOS 3® in the form of standard template library (STL) files. SLA 3D printer-built layers of an upper dental arch model were made by using liquid polymer hardened by laser beam (blue 405 nm laser). Each 3D SLA model was scanned from 56 positions and a section to check the precision of reconstruction. The model surface was evaluated with a profilometer, scanning electron microscope, and stereomicroscope. Differences between the intraoral scanned digital STL models and 3D SLA prints were very small, namely in hundredths of mm, and in many cases, they were also significant at lower levels. Stereolithography prepared fine-grained structures, the models were more homogeneous and smoother, and soft layering remains were visible if compared with plaster grainy surface structure showing sharp edges of orthorhombic crystals. The study has shown the precision of 3D SLA models along all three axes, a, b, c, in the whole model volume and also in cross-section. The advantages for dentistry are the colors: white, yellow and light brown; SLA models are stable and can be used repeatedly. In addition, a virtual database of models can save space in the dental office or lab.

Desiccation-induced alterations in surface topography of thylakoids from resurrection plant Haberlea rhodopensis studied by atomic force microscopy, electrokinetic and optical measurements.

With their ability to survive complete desiccation, resurrection plants are a suitable model system for studying the mechanisms of drought tolerance. In the present study, we investigated desiccation-induced alterations in surface topography of thylakoids isolated from well-hydrated, moderately dehydrated, severely desiccated and rehydrated Haberlea rhodopensis plants by means of atomic force microscopy (AFM), electrokinetic and optical measurements. According to our knowledge, so far, there were no reports on the characterization of surface topography and polydispersity of thylakoid membranes from resurrection plants using AFM and dynamic light scattering. To study the physicochemical properties of thylakoids from well-hydrated H. rhodopensis plants, we used spinach thylakoids for comparison as a classical model from higher plants. The thylakoids from well-hydrated H. rhodopensis had a grainy surface, significantly different from the well-structured spinach thylakoids with distinct grana and lamella, they had twice smaller cross-sectional area and were 1.5 times less voluminous than that of spinach. Significant differences in their physicochemical properties were observed. The dehydration and subsequent rehydration of plants affected the size, shape, morphology, roughness and therefore the structure of the studied thylakoids. Drought resulted in significant enhancement of negative charges on the outer surface of thylakoid membranes which correlated with the increased roughness of thylakoid surface. This enhancement in surface charge density could be due to the partial unstacking of thylakoids exposing more negatively charged groups from protein complexes on the membrane surface that prevent from possible aggregation upon drought stress.

Chester Nez and the Unbreakable Code: A Navajo Code Talker’s Story by Joseph Bruchac

Reviewed by: Chester Nez and the Unbreakable Code: A Navajo Code Talker’s Story by Joseph Bruchac Deborah Stevenson, Editor Bruchac, Joseph Chester Nez and the Unbreakable Code: A Navajo Code Talker’s Story; illus. by Liz Amini-Holmes. Whitman, 2018 [32p] ISBN 978-0-8075-0007-1 $16.99 Reviewed from galleys R Gr. 2–4 In this picture book biography, Chester Nez was only eight when he was sent to the Fort Defiance boarding school for Navajo children, where they were punished for speaking Navajo and told to focus on living in the white man’s world. When World War II broke out, however, that deprecated language was suddenly valuable as an unbreakable code (“Chester was proud he had never given up speaking Navajo”), and Navajos were sought to join the Marines. As one of the code talkers, Nez worked on the Pacific front, where the code helped the Allies defeat the Japanese; however, the horrors of battle and the need for sustained secrecy about his role left their mark on him until his family arranged a traditional Enemy Way ceremony that “restored Chester to the trail of beauty and the Right Way.” Bruchac takes the now-familiar information about the code talkers and gives it an illuminating personal and cultural frame, emphasizing the fact that it was Nez’s committed connection to his heritage that served both his country and, throughout his life, himself. The prose is spare yet thoughtfully chosen, compacting important ideas into accessible language, and the details about the creation of the code are intriguing. Moody, somber-toned art emphasizes texture in expressionistic brushstrokes and grainy paper surfaces; while the figures are sometimes awkward, there’s an iconic flavor in the softly blurred images. This has obvious use as a war story, but it’s also a compelling account of how a national effort is made stronger by diversity and how Nez forged a satisfying self-identity in the face of racism. End matter includes an author’s note detailing Chester Nez’s post-war life, a portion of the Navajo Code complete with translation, and a timeline. Copyright © 2018 The Board of Trustees of the University of Illinois

Effect of natural cross-linkers and drying methods on physicochemical and thermal properties of dried porcine plasma protein

Abstract Porcine plasma protein (PPP) is a good source of protein from a slaughterhouse by-product; however, modification of PPP is still needed to improve its properties. The effect of various natural cross-linkers (rutin; RT, caffeic acid; CA and genipin; GP) and different drying methods (freeze drying: FD and spray drying: SD) on the properties of PPP were investigated. Cross-linking with RT, CA and GP could markedly affect the color of the modified PPP. The freeze-dried modified PPP with RT exhibited the lowest free amino group contents while using CA and GP exhibited the lowest sulfhydryl group contents. The spray-dried modified PPP with RT had lower free amino group contents than CA and GP. Modification of PPP changed the molecular weight and FT-IR spectra of both freeze-dried and spray-dried samples. The scanning electron microscope images showed that all spray-dried modified PPP samples exhibited shrinkage with a spherical shape whereas freeze-dried modified PPP exhibited a rough, grainy surface. The freeze-dried modified PPP with GP improved the thermal properties of PPP. Thus, RT, CA and GP can be considered as alternative natural cross-linkers. Moreover, the drying method reflected the properties of dried PPP for final food application.