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The drying process of natural rubber latex significantly affects the structure of the raw rubber network and vulcanizate crosslinking network, resulting in various anti‐aging performances. In the present study, a microwave generator was used as an efficient source of clean energy; potassium oleate was introduced as a foaming agent to increase the porosity and water loss channel of the latex system. Aiming at dehydrating and drying natural rubber latex efficiently, an aging resistant rubber composite was prepared. Meanwhile, the mechanism of the foaming agent‐assisted microwave drying process on the raw rubber network and the cross‐linking network was studied. The experimental results show that the prepared rubber using by this process has higher plastic retention and fluidity. Moreover, it contains more non‐rubber components (e.g. protein and acetone extract) and better network structure of raw rubber and vulcanized rubber. It is found that applying this process increases the tensile product by 13.5% and the retention rate of the tensile product after aging by 15.3 times. This process is important for the development of the rubber industry in the direction of green environmental protection, energy conservation, and high efficiency. [ABSTRACT FROM AUTHOR]

Waterborne polyvinyl alcohol (PVA) films show lower environmental impact but render high residual solvent on account of hydrophilicity of PVA and low volatility of water. Plasticizers have shown high potential to act as drying enhancers in some recent studies. Plasticizers triphenyl phosphate (TPP) and polyethylene glycol (PEG400) with their favorable chemical structures and relatively low molar masses are promising options. Their performances in drying waterborne PVA films are compared with the plasticizers used in earlier works, at different initial wet film thicknesses, polymer contents, enhancer contents, and enhancer molar masses. Films were solvent casted by drying PVA‐water solutions in a substrate. TPP causes maximum lowering of the residual solvent and does this at high drying rate corresponding to low initial wet film thickness and PVA content. The least value of residual solvent is 0.20% at optimum TPP loading. The next best residual solvent results of 0.21% and 0.59% are, respectively, exhibited by PEG400 and PEG6000, but at low drying rate for high wet film thickness, for both the enhancers; however, at high drying rate for low wet film thickness anomalous skinning increased the residual solvent. At 0.51%, Capstone FS‐63 also gives good results and at high drying rate. Their relative performances are correlated to the viscosity of cast solutions, glass transition temperature of films (DSC), and chemical structures of the polymer and enhancers. TPP thus proved to be most effective. SEM showed dense films and disappearance of defects with optimum loading of TPP, and TGA/DTG showed thermally stable coatings. In spite of the higher cost of TPP it can have useful specialized applications that exploit its excellent flame retardance features. [ABSTRACT FROM AUTHOR]

Microencapsulation is considered an efficient technique to protect functional materials from oxidization while enabling controlled release. In this study, anti‐solvent precipitation was used to prepare zein‐based microcapsules loaded with Artemisia argyis essence (AAE@ZMs). The impact of different drying methods, namely vacuum drying, freeze drying, and spray drying on AAE@ZMs was evaluated. Quality of AAE@ZMs was evaluated by the determination of color, moisture content, bulk density, chemical structure, and morphology evaluation. Freeze dried AAE@ZMs (F‐AAE@ZMs) and vacuum dried microcapsules (V‐AAE@ZMs) respectively showed stronger water and oil absorption capacities. The residual content of Artemisia argyis essence (AAE) in V‐AAE@ZMs was higher than those in F‐AAE@ZMs and spray dried microcapsules (S‐AAE@ZMs) after continuously releasing for 120 h. Meanwhile, heated from 30 to 600°C, the residues of V‐AAE@ZMs and F‐AAE@ZMs were lower than those of S‐AAE@ZMs. Therefore, drying methods greatly affected key quality parameters of AAE@ZMs. This study provides guidance on the use of drying methods in microcapsules delivery systems with zein or other materials. [ABSTRACT FROM AUTHOR]

Chia oil has a high content of linolenic and linoleic acids, which are essential for the human body. However, their high degree of unsaturation (double bonds) makes the oil very susceptible to oxidation. In this context, the use of spray drying can be useful strategy to minimize the oxidation of this oil. Thus, the aim was to assess the effects of inlet temperature and feed rate conditions involved in the spray drying process on the physicochemical and morphological characteristics, and stability of the chia oil microparticles with maltodextrin and GA. The microparticles were obtained with a yield of 50%, encapsulation efficiency greater than 87%, low‐moisture content, and mean particle sizes ranging from 3.01 to 4.11 μm. The thermal evaluation and storage evidenced an increase in stability. The 1H HR‐MAS NMR technique showed that the microparticles maintained the characteristic fatty acid profile of chia oil and seeds. Results indicate that the microencapsulation methodology was suitable for preparing microparticles containing chia oil. [ABSTRACT FROM AUTHOR]

In order to overcome the environmental pollution or personal injury caused by precipitation of heavy metal ions during post‐processing and application of antimony‐catalyzed polyester industrial yarns, the titanium catalyst was used to prepare polyethylene terephthalate (PET) with high molecular weight, and then the titanium‐ catalyzed PET properties related to spinning kinetics were investigated as a basis for designing the drying, melting, spinning and extrusion, cooling, hot stretching and heat‐ setting process parameters. Compared with the spinning process of antimony‐catalyzed polyester of similar molecular weight, based on the lower melting point and melt viscosity of titanium‐catalyzed PET, the spinning temperature was lowered by about 5°C to reduce the thermal degradation of PET during extrusion, and the hot stretching speed and temperature were appropriately lowered based on the characteristics of low crystallization temperature and high crystallization rate in the heating process so that a product with a breaking strength of 8.29 cN/dtex was developed on an industrial device successfully. Titanium‐catalyzed high‐strength polyester industrial yarns, the structure and properties of crystal orientation, lamellar thickness, strength and elongation at break were comparable with those of antimony‐catalyzed polyester industrial yarns. [ABSTRACT FROM AUTHOR]

Anthocyanins are of increasing interest for food applications due to their health benefits. However, their poor stability and susceptibility to unfavorable environmental conditions may limit their application. Microencapsulation offers enhanced stability and controlled release properties. The aim was designing an ultrasonic encapsulator with a variable frequency ultrasonic driver to encapsulate black carrot and mahaleb anthocyanins. First, a double‐channel variable frequency and power adjustable ultrasonic driver and atomizer head were designed. The cooled gelation technique was used to encapsulate anthocyanin in an alginate‐gelatin complex. Freeze‐drying and air‐drying techniques were used for drying of microcapsules. Encapsulation parameters were atomization frequency, alginate, and anthocyanin concentrations. The capsules were characterized by encapsulation efficiency, particle diameter, and controlled release rates. Controlled release tests were performed at two different temperatures and pH values. Encapsulation efficiency was 87%–95%, mean diameters were between 69 and 95 μm. Maximum release rates were obtained from freeze‐dried mahaleb anthocyanin capsules. Release rates increased with increasing temperature and pH values. In addition, the experimental results showed that the increase in the amount of alginate used in encapsulation decreased the release rate. Moreover, the results proved that the designed encapsulator can be used for encapsulation in fields such as food, pharmaceuticals, polymers, chemistry, and materials. [ABSTRACT FROM AUTHOR]

ABSTRACT The effect of freeze-thaw pretreatment on the thermal drying process and physicochemical properties of chitosan was investigated in this study. Results showed that the freeze-thaw treatment changed the form of chitosan paste and reduced 75.6-77.7% of the water content. The freeze-thaw treatment decreased the drying time of chitosan from 16-19 h to 2.75-4 h and the dried product was loosely packed powder. After freeze-thaw treatment, the molecular weight of chitosan was unchanged during the thermal drying. The heat-induced browning effect of chitosan during drying was greatly alleviated by the pretreatment. Furthermore, the pretreatment increased the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity of dried product by 40.4-59.8%. The molecular weight, color, and DPPH radical-scavenging activity of the pretreated dried chitosan product were close to those of freeze-dried product. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41017. [ABSTRACT FROM AUTHOR]

ABSTRACT Uniformly dispersed carbon nanotubes (CNTs) reinforced ultrahigh molecular weight polyethylene (UHMWPE) composites were successfully prepared by freeze-drying method. Specifically, polymer powders were mixed with CNT aqueous paste, and then freeze-dried. As a consequence, CNTs covered at the surface of UHMWPE powders evenly when CNT content was not very high, which improved the quantity of crystals and crystallinity of UHMWPE/CNTs composites by providing more nucleation sites during the upcoming compression-molded process. Furthermore, optimized dispersion state of CNTs and concomitant higher crystallinity made freeze-drying technique prepared composites display much lower wear rate when compared with pure UHMWPE and UHMWPE/CNTs composites fabricated by common heat-drying method. In a word, our proposed method of freeze-drying is simple and effective for mass production of UHMWPE/CNTs composites, and it is promising to be applied to fabricate many kinds of nanofillers modified polymer composites, for example, polymer/graphene material. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41885. [ABSTRACT FROM AUTHOR]

ABSTRACT Amphiphilic methyl cellulose (MC) was used as the emulsifier and the internal wall material to increase the microencapsulation efficiency (ME) of tea tree oil (TTO) and the stability of the emulsion for spray-drying. The results of microscopy images, zeta potential, and microencapsulation efficiency indicated that the wall material components affected the morphology, stability, and ME of the microcapsules. The microcapsules with the wall materials of MC/chitosan (CTS)/alginate (ALG) were spherical and had higher ME than those with monocomponent or bicomponents of MC, CTS, or ALG, or triple components of MC/ALG/CTS. Spray drying conditions were optimized to find the optimum microencapsulation conditions. The highest ME 89.4% and the highest oil embedding rate (ER) 90.4% were obtained through spray-dying the emulsion of 0.8 mL TTO embraced by 0.4 g MC, 0.6 g CTS, and 3 g ALG at the drying conditions of inlet air temperature 210 °C, needling frequency 2 s, and pump flow rate 55 r/min. Microencapsulation obviously decreased the release of TTO. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44662. [ABSTRACT FROM AUTHOR]

To formulate therapeutic proteins into polymeric devices the protein is typically in the solid state, which can be achieved by the process of freeze-drying. However, freeze-drying not only risks denaturing the protein but it can adversely affect the cure characteristics of protein-loaded silicone elastomers. This study demonstrates that a variation in the parameters of the freeze-dryer can significantly affect the residual moisture content of freeze-dried BSA, which in turn has an effect on the bulk density and flow properties of the BSA. The bulk density and flow properties of the BSA subsequently affect the cure characteristics of BSA-loaded silicone elastomers. An increase in the residual moisture content results in the freeze-dried BSA having a decreased bulk density and poor flow properties which can have a detrimental effect on the cure characteristics of a freeze-dried BSA-loaded silicone elastomer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 [ABSTRACT FROM AUTHOR]

The utilization of alginate polymers for wound healing is well explored; however, little attention is paid toward the optimization of the manufacturing process, especially in regards to the final morphological and rheological properties that are imparted to the alginate matrix. This is important as it helps to establish a set of guidelines for the consistent fabrication of mechanically strong polymer wafers, which in the context of manufacturing and production contributes to the reduction in research and development time required. In this study, the order of application with respect to cross‐linking and freeze‐drying parameters has been investigated, which showed to result in distinct differences in terms of their overall morphology and mechanical strength. The application of freeze‐drying before cross‐linking results in the uniform distribution of cross‐links throughout the alginate wafer, thereby producing a mechanically strong polymer wafer that retains the dehydrated matrices original thickness and architecture. Based on the observed data, freeze‐drying prior to cross‐linking facilitates the increased permeation and distribution of the cross‐linker solution into the polymer matrix, thus resulting in the uniform distribution of ionic cross‐links, which is necessary to produce a more mechanically superior polymer matrix. [ABSTRACT FROM AUTHOR]

The article discusses a project initiated on the assumption that supersaturation of air in a polymer solution during drying can result to bubble or blister defects in the coating. It assumes that before and during the drying process, the polymer solution was exposed to a vapor environment where the activity of nitrogen is constant suggesting the likely occurrence of bubble formation in a nucleation site. The findings support all experimental observations about bubble formation.

Currently, microcapsules are attracting great attention and becoming more and more widely used in sustained release system. In this research, zein‐based microcapsules were prepared by anti‐solvent precipitation technology and spray drying. The properties of as‐prepared microcapsules were optimized by adjusting the reaction conditions and parameters such as the mass ratio of zein to vanillin, the drying temperature and whether polyethylene glycol was added or not. Meanwhile, the morphologies, chemical structures, and application performances of microcapsules were characterized and determined by SEM, FT‐IR, TG, and so on. The results showed that the morphology of as‐obtained microcapsules was a regular spherical shape with no cracks when the mass ratio of zein to vanillin was 1:1, the inlet temperature was 120 C and the polyethylene glycol was introduced. Meanwhile, it was also proved that the polyethylene glycol has a positive effect on the encapsulation efficiency in microcapsules. Moreover, zein microcapsules can effectively improve the thermal stability and release behavior of vanillin, meanwhile the exist of polyethylene glycol can further improve the properties of zein microcapsules. This research provided guidelines for the study of microcapsules. [ABSTRACT FROM AUTHOR]

Drying oils have been considered as water resistant coatings for bio-based packaging materials; however, their curing rates are slow for industrial applications. Infrared radiation was investigated in this study as a means to increase the curing rate of linseed and tung oils. The effect of oil pretreatment with gamma radiation was also investigated. FTIR spectroscopy was used to monitor chemical changes during oil oxidation. Results indicated that infrared radiation increased the curing rate of linseed and tung oils. The oxidation rate of both oils, as monitored by the decrease of the 3010 cm-1 FTIR peak, followed an exponential decay. The structure of cured films was examined by SEM. Images of films cross section were used to develop a qualitative model of the curing process. Linseed and tung oil showed differences in structural development during drying. In the case of linseed oil, the formation of a tough skin layer slowed down oxygen diffusion to the oil underneath, resulting in slow curing. For the case of tung oil, the skin layer shrank as it formed allowing oxygen diffusion and fast curing of tung oil. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [ABSTRACT FROM AUTHOR]

This paper prepared potassium oleate/silica/natural rubber composites by atomization spray drying technology. This study compared the effects of the environmental protection accelerator potassium oleate and amine accelerator 1,3‐diphenylguanidine on the Payne effect, silane reaction index, vulcanization performance, mechanical properties, static and dynamic mechanical properties, and aging properties of silica/natural rubber. The results show that potassium oleate can promote the silane reaction and increase the silane reaction's efficiency. When potassium oleate formed the silica coating, the carboxyl group of potassium oleate and the hydroxyl group of silica were bonded to form a covalent bond, which reduced the polarity of silica and promoted the dispersion effect of silica in the rubber matrix and enhanced the compatibility with rubber. Compared with the original formulation, after adding 3 phr of potassium oleate, the fracture elongation of vulcanized rubber was increased by 17.2%, tensile product increased by 57.3% and rolling resistance decreased by 54.6%. After adding 3 phr of 1,3‐diphenylguanidine, the fracture elongation of vulcanized rubber was increased by 1.1%, tensile product increased by 51.1% and rolling resistance decreased by 48.6%. In contrast, the anti‐aging performance of the rubber composites with potassium oleate was better than that of 1,3‐diphenylguanidine. This study opens up a new way to apply a new green rubber accelerator and prepare high‐performance rubber composites. [ABSTRACT FROM AUTHOR]