Preparation of coated thermo‐regulating textiles using Rubitherm‐RT31 microcapsules

Spherical microcapsules with a 49 wt % of Rubitherm^® RT31 were successfully synthesized by means of suspension‐like polymerization to be used for textile applications in summer conditions. Microcapsules were fixed into seven fabric substrates for different textile applications by a coating technique without deteriorating original functionalities of the textiles. Thermal performance of different coated textiles with 35 wt % of microcapsules was evaluated by differential scanning calorimetry (DSC) and infrared thermography (IR) techniques and the physical characteristics of textiles with thermo‐regulating properties were examined by environmental scanning electron microscopy (ESEM). It was observed that all treated textile substrates allow to obtain thermo‐regulating properties with acceptable latent heat storage capacities. Results also indicated that the presence of microcapsules containing Rubitherm^® RT31 produces a significant thermal insulation effect during a cold to warm transition (20–45°C). Thus, this kind of microcapsules can be used to obtain textiles with thermal comfort‐related properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Thermal and antimicrobial evaluation of cotton functionalized with a chitosan–zeolite composite and microcapsules of phase‐change materials

Antimicrobial cotton was developed with silver zeolites (SZs). Three different application approaches for the cotton surface functionalization were followed: (1) SZ alone, (2) SZ combined with chitosan film, and (3) chitosan–zeolite (CS–SZ) composites previously synthesized by a gelation process with sodium tripolyphosphate. All finishes were applied to the textile materials through conventional pad–dry–cure processes, and the obtained results were then compared. The resulting materials were characterized with Fourier transform infrared spectroscopy, scanning electron microscopy with energy‐dispersive X‐ray spectroscopy, differential scanning calorimetry, IR thermography, and contact angle measurements, and the antimicrobial activity was evaluated. The results suggest that the application of CS–SZ should be recommended for the production of textiles with antibacterial properties because the materials showed activity against Escherichia coli, Staphylococcus aureus, Candida albicans, and Trichophyton rubrum. In addition, the finishing can be combined with the application of microcapsules of phase‐change materials to obtain textiles with thermoregulating properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46135.     

Applying the sol–gel method to the deposition of nanocoats on textiles to improve their abrasion resistance

The thin-coat finishing of textiles carried out by the sol–gel methods gain greater and greater importance owing to their suitability for the versatile functionalization of textiles to impart to them properties being difficult and even impossible to obtain with the use of conventional finishing methods. This article presents the test results of the thin-coat protective finishing of cotton fabrics against abrasion. This treatment consists in depositing hybrid SiO₂*/Al₂O₃ sols synthesized from two precursors: (3-glycidoxypropyl)trimethoxy-silane and aluminum isopropoxide on fiber/fabric surface. The abrasion resistance of the fabric treated by the sol–gel method has been increased by about five times according to Martindale test and this effect is resistant to prolonged laundering. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

预处理对微胶囊改性聚酯织物舒适凉爽性的影响

由于聚酯纤维的化学性质稳定、纤维表面光滑,不易与后整理剂相结合,因此利用薄荷油微胶囊后整理对聚酯织物进行舒适凉爽改性时,存在附着量少、改性效果差的缺点。为解决这一问题,本文在后整理前增加了碱预处理和等离子体预处理。通过对聚酯织物原样、无预处理后整织物、碱预处理后整织物和等离子体预处理后整织物进行舒适凉爽性能测试,深入分析两种预处理方法对聚酯织物改性效果的影响。结果表明：等离子体预处理在织物透湿、导水、润湿、速干和凉爽性改性方面促进作用更明显,相比无预处理后整织物,等离子体后整织物的透湿率、经向和纬向芯吸高度、滴水扩散时间、蒸发速率及接触凉感系数分别提高了3.32%、40.24%、27.25%、80.39%、21.21%和5.59%;碱预处理则在织物透气性和吸水性改善方面的效果更佳,相比无预处理的后整织物,可将织物的透气率和吸水率分别提高43.43%和13.03%。因此,两种预处理方法对聚酯织物舒适凉爽性的改性效果有显著促进作用。     

Solar-absorbing metamaterial microencapsulation of phase change materials for thermo-regulating textiles

This paper presents a novel concept for designing solar-absorbing metamaterial microcapsules of phase change materials (PCMs) integrated with thermo-regulating smart textiles intended for coats or garments, especially for wear in space or cold weather on earth. The metamaterial is a periodically nanostructured metal-dielectric-metal thin film and can acquire surface plasmons to trap or absorb solar energy at subwavelength scales. This kind of metamaterial microencapsulation is not only able to take advantage of latent heat that can be stored or released from the PCMs over a tunable temperature range, but also has other advantages over conventional polymer microencapsulation of PCMs, such as enhanced thermal conductivity, improved flame-retardant capabilities, and usage as an extra solar power resource. The thermal analysis for this kind of microencapsulation has been done and can be used as a guideline for designing integrated thermo-regulating smart textiles in the future. These metamaterial microcapsules may open up new routes to enhancing thermo-regulating textiles with novel properties and added value.     

Coatings with metallic effect pigments for antimicrobial and conductive coating of textiles with electromagnetic shielding properties

Effect pigments were originally developed to realize advanced optical effects by coating on several types of material surfaces. However, metallic effect pigments are expected to be valuable for many other applications, such as antimicrobial effects, electrical conductive coatings, or shielding against radio waves (electromagnetic shielding). Accordingly, the aim of this article is to evaluate the advanced properties which can be realized by application of coatings containing metallic effect pigments onto textile materials leading to new functional textiles. In total, four different metallic effect pigments were investigated and compared to silver and graphite pigments. By application of coatings with copper- or silver-containing effect pigments significant antibacterial properties against E. coli and S. aureus can be realized. To achieve electric conductive textiles, which also enable effective shielding against radio waves, a copper pigment carrying a silver coating leads to the best properties. Altogether, an effective coating method is presented to achieve functional textiles that offer a broad range of possible applications.     

Chitosan microcapsules: Methods of the production and use in the textile finishing

Biopolymeric chitosan is considered a promising encapsulating agent for textile applications due to its biocompatibility, lack of toxicity, antibacterial activity, high availability, and low cost. After cellulose, it is nature's most important organic compound. Also, chitosan has unique chemical properties due to its cationic charge in solution. Microencapsulation technologies play an important role in protecting the trapped material and in the durability of the effect, controlling the release rate. The application of chitosan microcapsules in textiles follows the current interest of industries in functionalization technologies that give different properties to products, such as aroma finish, insect repellency, antimicrobial activity, and thermal comfort. In this sense, methods of coacervation, ionic gelation, and LBL are presented for the production of chitosan-based microcapsules and methods of textile finishing that incorporate them are presented, bath exhaustion, filling, dry drying cure, spraying, immersion, and grafting chemical. Finally, current trends in the textile market are identified and guidance on future developments.     

Synthesis and thermal properties of poly(n‐butyl acrylate)/n‐hexadecane microcapsules using different cross‐linkers and their application to textile fabrics

This study focused on the preparation, characterization, and determination of thermal properties of microencapsulated n‐hexadecane with poly(butyl acrylate) (PBA) to be used in textiles with heat storage property. Microcapsules were synthesized by emulsion polymerization method, and the particle size, particle size distribution, shape, and thermal storage/release properties of the synthesized microcapsules were analyzed using Fourier‐transform infrared spectroscopy, scanning electron microscopy, and differential scanning calorimetry techniques. Allyl methacrylate, ethylene glycol dimethacrylate, and glycidyl methacrylate were used as cross‐linkers to produce unimodal particle size distribution. MicroPBA microcapsules produced using allyl methacrylate cross‐linker were applied to 100% cotton and 50/50% cotton/polyester blend fabrics by pad‐cure method. The mean particle size of microcapsules ranges from 0.47 to 4.25 μm. Differential scanning calorimetry analysis indicated that hexadecane in the microcapsules melts at nearly 17°C and crystallizes at around 15°C. The contents of n‐hexadecane of different PBA microcapsules were in the range of 27.7–50.7%, and the melting enthalpies for these ratios were between 65.67 and 120.16 J/g, respectively. The particle size and thermal properties of microcapsules changed depending on the cross‐linker type. The cotton and 50/50% cotton/polyester blend fabrics stored 6.56 and 28.59 J/g thermal energy, respectively. The results indicated that PBA microcapsules have the potential to be used as a solid‐state thermal energy storage material in fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Intumescent Fireproof Coating Based on Water Glass

Abstract

The effectiveness of fireproof intumescent coatings based on water glass can be considerably increased if the coagulated sodium water glass is used as an intumescent component. When heated, the coagulated sodium water glass creates a steam-gas cloud above the protected surface which together with foam formation decreases the temperature of the protected surface. The mixture of sodium water glass, portland cement and dehydrated clay which, besides adhesion, maintain the durability of the composition are used as binders due to their cohesive properties.     

Dendrimer finishing influence on CO/PES blended fabrics color assessment

Textile finishing includes all processes that help to maintain the value or increase the value of the textile material. It encompasses dyeing, printing, and all the finishing treatments to realize durable press, soil release, flame retardant, antistatic, antimicrobial, or water/oil repellency properties. When these properties are realized on dyed textile fabric, one effect could be ascribed to the color change induced by finishing operations. This research focuses on the assessment of color alterations occurring on the dyed cotton/polyester blended fabrics due to the nanoparticle‐sized dendrimer (DWR), dendrimer–fluorocarbon (DWOR), and fluorocarbon (FWOR) finishing onto their surfaces. The dependence of color on the surface state of treated textiles is calculated in the context of spectrophotometric measurements. Modification of the surface roughness by reflectance spectrum and the absorbance of finishes in visible range were investigated to determine color changes between the original (control fabric, dyed but not treated) and treated fabrics. As a result of color matching calculated by CIE‐Lab values, color change is related to the surface roughness associated with absorbance values of applied finishes. In addition, fabrics mechanical properties were evaluated to estimate if finishing agents application gives rise to other changes, besides color alterations. The fabrics mechanical properties have been found not significantly altered by the aforementioned finishing treatments. These results could be applied for industrial needs (quality control), or in the artistic field of conservation, or restoration (to follow the color of paintings). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Characterization of the Plasticized GAP/PEG and GAP/PCL Block Copolyurethane Binder Matrices and its Propellants

Though glycidyl azide polymer (GAP) is a well‐known and promising energetic polymer, propellants based on it suffer from poor mechanical and low‐temperature properties. To overcome these problems, plasticized GAP‐based copolymeric binders were prepared and investigated through the incorporation of flexible‐structural polyethylene glycol (PEG) and polycaprolactone (PCL) into a binder recipe under a Desmodur N‐100 polyisocyanate (N‐100)/isophorone diisocyanate (IPDI) (2 : 1, wt. ratio) mixed curative system. The nitrate esters (NEs) or GAP oligomer were used as energetic plasticizers at various ratios to the polymers. The GAP/PCL binders held the plasticizers much more than the GAP/PEG binders did. The glass transition temperatures (T_g) of segmented copolymeric binders were more dependent on the plasticizer level than the PEG or PCL content. The increase in the plasticizer content decreased the mechanical strength and modulus of binders, while the change of strain was modest. Finally, the NE plasticized GAP‐based solid propellants showed enhanced mechanical and thermal properties by the incorporation of PEG or PCL. The properties of GAP/PCL propellants were superior to those of GAP/PEG propellants.     

Fragrant finishing of cotton with microcapsules: comparison between printing and impregnation

Microencapsulated fragrance was used to produce a fragrant textile product. Melamine–formaldehyde polymer wall microcapsules with a lavender, rosemary and sage essential oil core were applied to a cotton fabric in two ways, i.e. byscreen printing and impregnation. The samples were dried and cured, and then the differences between them were analysed. The condition and distribution of applied microcapsules were observed by scanning electron microscopy, fragrance evaluation was performed on printed and impregnated samples after they had been washed several times, and their handle properties were investigated. Moreover, the influence of artificial light on the wall of microcapsules was examined, and possible antibacterial activity against Staphylococcus aureus and Escherichia coli was evaluated. The change in colour of all samples as a consequence of the addition of microcapsules to the paste or bath was checked. The results show that both application techniques are appropriate for the effective fragrant but on the other hand ineffective antibacterial finishing of cotton fabrics. Artificial light did not affect the microcapsules. There is an impact on colour only when the capsules are printed to fabric. Both of the techniques used, printing and impregnation, have advantages as well as drawbacks.     

Paper coating performance of hemicellulose-rich natural polymer from distiller's grains

Coatings contribute to about 10% of the overall cost of paper production of which, the binder is the highest cost component in the formulation. In addition to costs, the binders that are currently being used are synthesized from fossil fuel feedstock raising concerns towards the sustainability of paper coatings. Furthermore, papers coated with waxes, polyolefins and other synthetic materials are difficult to recycle or compost. These challenges inherent with synthetic binders can be addressed by using renewable, plant based binders. This research focused on an abundant and underutilized source of hemicellulose based binders (DG gum) that can be extracted from distiller's dried grains. The extracted binder was compared with polyvinyl alcohol (PVA) in a coating formulation consisting of 10:1 CaCO₃ to binder formulation coated on light weight paper. Cobb test, dry and wet tensile tests, optical properties (brightness, color, opacity), water vapor transmission rate (WVTR) analysis were performed to compare the hemicellulose based binder with PVA. The results indicate water absorptivity reduction by 25% for both DG gum and PVA coatings from the base paper value. Dry tensile index was lower with higher coating weights for both coatings with similar performance. The performance on WVTR analysis for both coatings was also comparable. No significant differences in optical properties after coating were observed from that of the base paper. These results suggest that hemicellulose based binder extracted from distiller's grains has the potential to replace synthetic binders in paper coating formulations.     

纺织品用有机硅的合成和应用

含硅的表面活性剂是一种具有优良性能的功能性表面活性剂 ,用于纺织品整理可赋予织物柔软、滑爽、抗静电、疏水、耐热等优异性能。本文综述了各种改性有机硅在纺织品整理方面的应用 ,并介绍了它们的合成方法 ,归纳了常用改性有机硅油的合成机理。针对改性有机硅不同的化学结构和性能特点 ,归纳了它们适用于何种织物的整理。     

Self-healing of polystyrene block–polyisoprene block–polystyrene

Abstract

The addition of self-healing properties to polystyrene block–polyisoprene block–polystyrene by loading the polymeric matrix with microcapsules filled with monomer [dicyclopentadiene (DCPD)] and first generation Grubbs catalyst is described in detail. The confinement of DCPD in polyurea formaldehyde microcapsules has been demonstrated by Raman spectroscopy. The above mentioned components (polymeric matrix, microcapsules filled with monomer and catalyst) have been mixed in solution, and the solvent has been slowly evaporated. The polymerisation of the monomer (DCPD) within the self-healed polymeric system after the fracture of microcapsules has been confirmed by Raman spectroscopy. Slow stress–strain mechanical testing has confirmed the efficiency of the added self-healing capabilities.     

Modelling method based on idealised fibre bundles

Abstract

In the fibrous structures such as textiles and composites there are fibre assemblies exhibiting statistical bundle like behaviour. This paper presents a modelling method and software FibreSpace, based on a system of structuralised statistical fibre bundles, so called fibre bundle cells. These fibre bundle cells introduced before represent different idealised and typified fibre properties such as fibre shape, state of deformation, gripping as a connection with the vicinity, and the characteristic of force-transmitting and damage. With the help of the weighted parallel connection of the fibre bundle cells the mechanical behaviour and the damage process of real fibrous systems can be modelled as well as some structural properties or the strength data of single fibres can be determined by a fibre bundle cells model identified on the basis of measurements. The applicability of the fibre bundle cells method and modelling program developed is demonstrated by modelling the load and damage process of real textile structures and unidirectional composites during tensile or flexural test.     

壳聚糖/明胶抗菌微胶囊的制备及其应用

为了制备用于棉织物天然抗菌整理剂,以绿苋、龙葵和黄柏的复配提取物为芯材,壳聚糖-明胶为壁材,采用复凝聚法制备抗菌微胶囊。研究了乳化剂含量、剪切速度、pH对微胶囊的外观形态及尺寸的影响;借助扫描电子显微镜、傅里叶红外光谱仪等对样品进行表征;将抗菌微胶囊用于棉织物的整理并测试其抗菌性能。结果表明：初乳中乳化剂质量分数为5%、剪切速度为8000r/min、pH为5.7为最佳制备条件,制得的微胶囊尺寸分布在1480～3580nm且热稳定性良好;当微胶囊质量浓度为25g/L,黏合剂质量分数为5%,热烘温度为40℃,整理试样对金黄色葡萄球菌和大肠杆菌的抑菌率分别为89.30%和81.43%,且抑菌效果持久。     

Aromatic polyetherimides as promising fusible film binders

Polyetherimides (PEI) based on dianhydrides of 3,3′, 4,4′-dipheniloxytetracarboxylic acid and 1,3-bis-(3,4-di-carboxyphenoxy)benzene that contain fragments of such thermoplastic polymers as poly(ether sulfone) or poly(phenylene oxide) have been synthesized. Thermoplastic properties of synthesized PEI were characterized by flow temperature T_f and melt viscosity η_m. The properties obtained are outstanding for the production of PEI as fusible film binders, and composites can be produced without toxic solvents. Carbon fiber reinforced plastics (CFRP) based on PEI films were analyzed using an Acoustic Emission (AE) technique.     

Reactive Energetic Plasticizers for Energetic Polyurethane Binders Prepared via Simultaneous Huisgen Azide‐Alkyne Cycloaddition and Polyurethane Reaction

Reactive energetic plasticizers (REPs) for use in glycidyl azido polymer (GAP) based polyurethane (PU) energetic binders were investigated. These REPs consisted of an activated terminal alkyne group that was expected to give rise to Huisgen azide‐alkyne 1,3‐dipolar cycloaddition within the specific pot life for a PU formulation to prevent the migration of plasticizers, and with a gem‐dinitro group as an energy resource. A quantitative miscibility investigation between the plasticizers and uncured GAP showed that REPs exhibited better miscibility than conventional energetic plasticizers. The plasticization effect of the REPs on the GAP prepolymer with respect to the reduction of the viscosity illustrated REPs can effectively reduce the viscosity of the GAP prepolymer from 6,015 cP to 150–240 cP at the processing temperature when 50 wt‐% of REP was added. A comparison of the click reactivity and activation energies (E_a) of REPs and GAP prepolymer elucidated that the reactivity of azide‐alkyne cycloaddition depended on the dipolarophilicity of REPs which could be controlled by adjusting the length of methylene spacer between electron‐withdrawing groups (EWG) and neighboring alkynes in REPs. Thermogravimetric analysis manifested REP/GAP‐based PU binders maintained the thermal stability of the control GAP‐based PU binder. The mechanical properties and impact insensitivity of the GAP‐based PU binders were also improved by the incorporation of REPs.     

Drying of Pharmaceuticals: The Applicability of Spouted Beds

ABSTRACT

This study evaluates the performance of conventional spouted beds (CSB) with inert bodies in the drying of pharmaceutical pastes, based on the dry product quality. The powder obtained by drying annatto extracts shows properties comparable to one of the commercial products, indicating that the spouting is competitive with other industrial and lab-scale processes. The contents of bixin and caffeine in annatto and guarana dry powders demonstrated a strong dependence on the inlet air temperature. Also, the properties of indomethacin-containing microcapsules dried in CSB and spray dryers revealed that spouting is a promising technique to obtain pharmaceutical forms with unique drug release qualities.