TY - CONF TI - Developments in the Production of High Surface Area Fibers and Nonwovens for Filtration AU - Pourdeyhimi, B. T2 - Society of Plastics Engineers C2 - 2015/3/23/ CY - Orlando, FL DA - 2015/3/23/ PY - 2015/3/23/ ER - TY - CONF TI - Creating Tissues from Textiles: Scalable Novel Nigh Surface Area Gilled Fiber Scaffolds for Tissue Engineering Applications Using Commercially Relevant Nonwoven Manufacturing Approaches AU - Tuin, S.A. AU - Pourdeyhimi, B. AU - Loboa, E.G. T2 - 17th Annual North Carolina Tissue Engineering and Regenerative Medicine Society Conference C2 - 2015/10// C3 - Proceedings of the 17th Annual North Carolina Tissue Engineering and Regenerative Medicine Society Conference CY - Winston Salem, NC DA - 2015/10// PY - 2015/10// ER - TY - CONF TI - From Textiles to Tissues: Economical, Scalable, Textile Industry Standard Nonwovens for Tissue Engineering Applications AU - Tuin, S.A. AU - Pourdeyhimi, B. AU - Loboa, E.G. T2 - Biomedical Engineering Society: Cellular and Molecular Bioengineering 2015 Annual Meeting C2 - 2015/1// CY - Saint Thomas, US Virgin Islands DA - 2015/1// PY - 2015/1// PB - US Virgin Islands ER - TY - JOUR TI - Nonwovens modelling: a review of finite-element strategies AU - Farukh, Farukh AU - Demirci, Emrah AU - Ali, Hassan AU - Acar, Memiş AU - Pourdeyhimi, Behnam AU - Silberschmidt, Vadim V. T2 - The Journal of The Textile Institute AB - This paper reviews the main strategies used to simulate the mechanical behaviour of nonwoven materials that is defined by a structure of their fibrous networks and a mechanical behaviour of constituent fibres or filaments. The main parameters influencing the network structure of nonwoven materials are discussed in the first part. The second part deals with two main strategies employed in the analysis of mechanical behaviour of nonwoven materials using finite-element models based on continuous and discontinuous techniques. Both strategies have further subtypes, which are critically reviewed, and future trends in this area of research are discussed. DA - 2015/3/16/ PY - 2015/3/16/ DO - 10.1080/00405000.2015.1022088 SP - 1-8 J2 - The Journal of The Textile Institute LA - en OP - SN - 0040-5000 1754-2340 UR - http://dx.doi.org/10.1080/00405000.2015.1022088 DB - Crossref KW - nonwovens KW - mechanical properties KW - thermal bonding KW - finite-element modelling ER - TY - JOUR TI - Service life of circular pleated filters vs. that of their flat counterpart AU - Saleh, A.M. AU - Tafreshi, H. Vahedi AU - Pourdeyhimi, B. T2 - Separation and Purification Technology AB - In this note, an easy-to-use two-dimensional model is developed to predict the instantaneous pressure drop and collection efficiency of circular pleated filters as a function of time in both the surface and depth filtration regimes. Our model uses average velocity profiles that represent the flow field inside a circular pleated filter to circumvent the need for conducting CPU-intensive CFD calculations to predict the service life of a circular filter. This is accomplished by considering a reasonable dust-cake profile inside the pleat channels as a function of the flow and particles properties, and allowing the cake to grow as the filter continues to collect particles over time. Despite the approximate nature of its predictions, the speed at which a large parameter study can be completed makes the present model very valuable for design and development of circular pleated filters. Using this model for instance, it can be shown quantitatively that circular filters with high inlet-to-outlet diameter ratios outperform their flat counterparts. DA - 2015/12// PY - 2015/12// DO - 10.1016/J.SEPPUR.2015.09.041 VL - 156 SP - 881-888 J2 - Separation and Purification Technology LA - en OP - SN - 1383-5866 UR - http://dx.doi.org/10.1016/J.SEPPUR.2015.09.041 DB - Crossref KW - Circular pleated filters KW - Dust-loaded filters KW - Modeling filtration ER - TY - CHAP TI - Deformation and Damage of Thermally Bonded Nonwoven Networks AU - Farukh, Farukh AU - Demirci, Emrah AU - Acar, Memiş AU - Pourdeyhimi, Behnam AU - Silberschmidt, Vadim V. T2 - Mechanics of Advanced Materials AB - Nonwovens, composed of randomly-oriented polymer-based fibres, possess unique properties, with features common to paper, plastic and textile materials. From various types of bonding technologies used in the nonwovens industry. This chapter focuses on thermal bonding and respective fabrics as it is one of the most widely used techniques. Understanding a mechanical behaviour of polymer-based nonwoven materials that includes large-strain deformation and damage can help to evaluate a response of nonwoven fibrous networks to various loading conditions. The main deformation and damage mechanisms are analysed by means of experimental assessment of fabrics in tension alongside damage evolution based on progressive failure of fibres. Finite-element simulation strategies to gain insight into their behaviour and to achieve quantitative exploration of a design space for these materials are also discussed in this chapter. PY - 2015/// DO - 10.1007/978-3-319-17118-0_8 SP - 181-199 OP - PB - Springer International Publishing SN - 9783319171173 9783319171180 UR - http://dx.doi.org/10.1007/978-3-319-17118-0_8 DB - Crossref ER - TY - JOUR TI - Translating textiles to tissue engineering: Creation and evaluation of microporous, biocompatible, degradable scaffolds using industry relevant manufacturing approaches and human adipose derived stem cells AU - Haslauer, Carla M. AU - Avery, Matthew R. AU - Pourdeyhimi, Behnam AU - Loboa, Elizabeth G. T2 - JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART B-APPLIED BIOMATERIALS AB - Polymeric scaffolds have emerged as a means of generating three-dimensional tissues, such as for the treatment of bone injuries and nonunions. In this study, a fibrous scaffold was designed using the biocompatible, degradable polymer poly-lactic acid in combination with a water dispersible sacrificial polymer, EastONE. Fibers were generated via industry relevant, facile scale-up melt-spinning techniques with an islands-in-the-sea geometry. Following removal of EastONE, a highly porous fiber remained possessing 12 longitudinal channels and pores throughout all internal and external fiber walls. Weight loss and surface area characterization confirmed the generation of highly porous fibers as observed via focused ion beam/scanning electron microscopy. Porous fibers were then knit into a three-dimensional scaffold and seeded with human adipose-derived stem cells (hASC). Confocal microscopy images confirmed hASC attachment to the fiber walls and proliferation throughout the knit structure. Quantification of cell-mediated calcium accretion following culture in osteogenic differentiation medium confirmed hASC differentiation throughout the porous constructs. These results suggest incorporation of a sacrificial polymer within islands-in-the-sea fibers generates a highly porous scaffold capable of supporting stem cell viability and differentiation with the potential to generate large three-dimensional constructs for bone regeneration and/or other tissue engineering applications. DA - 2015/7// PY - 2015/7// DO - 10.1002/jbm.b.33291 VL - 103 IS - 5 SP - 1050-1058 SN - 1552-4981 KW - porous scaffolds KW - bone tissue engineering KW - Islands-In-The-Sea KW - human adipose-derived stem cells ER - TY - JOUR TI - Systematic study of trimethyl aluminum infiltration in polyethylene terephthalate and its effect on the mechanical properties of polyethylene terephthalate fibers AU - Padbury, Richard P. AU - Jur, Jesse S. T2 - JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A AB - Hybrid organic–inorganic materials are of increasing interest in the development of novel materials that unite characteristic properties of both organic and inorganic constituents. This work provides a mechanistic understanding of the processing space necessary to utilize hybrid modifications to produce advanced high strength fibrous and textile materials. The infiltration of organometallic precursors into fiber forming polymers and the subsequent formation of a hybrid material interface is detailed. To explore this in more detail, in-situ quartz crystal microgravimetry is employed to investigate the infiltration of trimethyl aluminum (TMA) into polyethylene terephthalate polymer films. Specifically, films with varied crystallinities are explored demonstrating that an increase in crystallinity results in a decrease in mass uptake of trimethyl aluminum. Subsequently, the authors highlight the structure–property relationships between modified and unmodified fibers infiltrated with TMA. For the first time, increases in peak load and elongation is observed by facile exposure to organometallic vapors. The combined peak load and elongation increase is an exciting outcome typically not observed in synthetic fibers. DA - 2015/1// PY - 2015/1// DO - 10.1116/1.4898435 VL - 33 IS - 1 SP - SN - 1520-8559 ER - TY - JOUR TI - Measuring electrostatic properties of fibrous materials: A review and a modified surface potential decay technique AU - Kilic, Ali AU - Shim, Eunkyoung AU - Pourdeyhimi, Behnam T2 - JOURNAL OF ELECTROSTATICS AB - Electrostatic charging of fibrous materials are of concern for the performance of electret filters and comfort issues of textiles. However there is a huge controversy in the characterization techniques of ion beam irradiated or corona charged fibrous materials. In this study we reported a reliable, simple surface potential measurement method. Large variations in potential measurements were found to be mostly due to structural nonuniformity such as packing density, thickness and fiber–fiber proximity. Test samples were prepared after optimizing those parameters and we were able to reduce coefficient of variation below 15%. Methods that were developed so far were also reviewed. DA - 2015/4// PY - 2015/4// DO - 10.1016/j.elstat.2014.12.007 VL - 74 SP - 21-26 SN - 1873-5738 KW - Surface potential decay test KW - Electret KW - Corona KW - Fibers ER - TY - JOUR TI - Thermal Stability of Gold Nanoparticles Embedded within Metal Oxide Frameworks Fabricated by Hybrid Modifications onto Sacrificial Textile Templates AU - Padbury, Richard P. AU - Halbur, Jonathan C. AU - Krommenhoek, Peter J. AU - Tracy, Joseph B. AU - Jur, Jesse S. T2 - LANGMUIR AB - The stability and spatial separation of nanoparticles (NP’s) is essential for employing their advantageous nanoscale properties. This work demonstrates the entrapment of gold NP’s embedded in a porous inorganic matrix. Initially, gold NP’s are decorated on fibrous nylon-6, which is used as an inexpensive sacrificial template. This is followed by inorganic modification using a novel single exposure cycle vapor phase technique resulting in distributed NP’s embedded within a hybrid organic-inorganic matrix. The processing is extended to the synthesis of porous nanoflakes after calcination of the modified nylon-6 yielding a porous metal oxide framework surrounding the disconnected NP’s with a surface area of 250 m2/g. A unique feature of this work is the use of a transmission electron microscope (TEM) equipped with an in situ annealing sample holder. The apparatus affords the opportunity to explore the underlying nanoscopic stability of NP’s embedded in these frameworks in a single step. TEM analysis indicates thermal stability up to 670 °C and agglomeration characteristics thereafter. The vapor phase processes developed in this work will facilitate new complex NP/oxide materials useful for catalytic platforms. DA - 2015/1/27/ PY - 2015/1/27/ DO - 10.1021/la504094g VL - 31 IS - 3 SP - 1135-1141 SN - 0743-7463 ER - TY - JOUR TI - Scalable Liquid Shear-Driven Fabrication of Polymer Nanofibers AU - Smoukov, Stoyan K. AU - Tian, Tian AU - Vitchuli, Narendiran AU - Gangwal, Sumit AU - Geisen, Pete AU - Wright, Miles AU - Shim, Eunkyoung AU - Marquez, Manuel AU - Fowler, Jeffrey AU - Velev, Orlin D. T2 - ADVANCED MATERIALS AB - A simple process for batch or continuous formation of polymer nanofibers and other nanomaterials in the bulk of a sheared fluid medium is introduced. The process may be of high value to commercial nanotechnology, as it can be easily scaled up to the fabrication of staple nanofibers at rates that may exceed tens of kilograms per hour. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. DA - 2015/4/24/ PY - 2015/4/24/ DO - 10.1002/adma.201404616 VL - 27 IS - 16 SP - 2642-2647 SN - 1521-4095 KW - antisolvents KW - composite nanofibers KW - liquid shearing KW - nanofibers KW - nanoribbons ER - TY - JOUR TI - Electrostatic Capture Efficiency Enhancement of Polypropylene Electret Filters with Barium Titanate AU - Kilic, Ali AU - Shim, Eunkyoung AU - Pourdeyhimi, Behnam T2 - AEROSOL SCIENCE AND TECHNOLOGY AB - This study reports on the effects of BaTiO3—a high dielectric constant additive—addition on charging and filtration properties of meltblown polypropylene (PP) electret filters. Since electrostatic capture efficiency of electret filters is mainly dependent on electrical forces, surface potential and aerosol filtration properties were analyzed and compared. Due to quasi-permanent nature of electret property, stability of charging and filtration performance was also investigated via following an isothermal charge decay procedure. Addition of BaTiO3 did not alter fiber morphology significantly. Particularly, the stability of electrostatic filtration performance was found to be promising with the addition of BaTiO3. Possible microstructural changes after addition of BaTiO3 were investigated via wide angle X-ray diffraction. Changes in crystal structure of PP upon addition of BaTiO3 did not deteriorate electrostatic properties.Copyright 2015 American Association for Aerosol Research DA - 2015/8/3/ PY - 2015/8/3/ DO - 10.1080/02786826.2015.1061649 VL - 49 IS - 8 SP - 666-673 SN - 1521-7388 ER - TY - JOUR TI - Application of solution-blown 20-50 nm nanofibers in filtration of nanoparticles: The efficient van der Waals collectors AU - Sinha-Ray, Sumit AU - Sinha-Ray, Suman AU - Yarin, Alexander L. AU - Pourdeyhimi, Behnam T2 - JOURNAL OF MEMBRANE SCIENCE AB - In this work filtration efficiency of commercially available filter media with fiber/pore sizes of the scale of 10 μm is dramatically increased by not only adding electrospun nanofibers, as is usually done, but also a layer of ultrafine supersonically blown 20–50 nm nanofibers. Three different commercially available base filters were modified with (i) electrospun nanofibers alone, (ii) solution-blown 20–50 nm nanofibers alone, and (iii) the dual coating with electrospun nanofibers deposited first and the solution-blown 20–50 nm nanofibers deposited on top of them. Detailed observations of nanoparticle removal by these base and the above-mentioned modified filters revealed that the filters with dual electrospun nanofibers (deposited first) and the solution-blown 20–50 nm nanofibers deposited on top of them are the most effective in removing the below-200 nm Cu nanoparticles/clusters from aqueous suspensions. Experiments were conducted in two different time ranges: (a) for 8–15 s, and (b) for 8 min. It was found that the efficiency of the dual-coated filters containing 20–50 nm fibers was significantly higher than those of the others at the lowest nanoparticle concentrations of 0.2–0.5 ppm in suspension. The experiments conducted for longer time revealed that the smallest nanofibers were as efficient in particle retention as in the shorter-time experiments, and there was no visible breakage pattern of these nanofibers. The theory developed in the present work explains and describes how the smallest solution-blown nanofibers introduce a novel physical mechanism of nanoparticle interception (the attractive van der Waals forces) and become significantly more efficient collectors compared to the larger electrospun nanofibers. The theory predicts the domain of nanoparticle collection due to the van der Waals forces. The theory also elucidates the morphology of the nanoparticle clusters being accumulated at the smallest nanofiber surfaces, including the clusters growing at the windward side, or in some cases also on the leeward side of a nanofiber. DA - 2015/7/1/ PY - 2015/7/1/ DO - 10.1016/j.memsci.2015.02.026 VL - 485 SP - 132-150 SN - 1873-3123 KW - Filtration of nanoparticles KW - Supersonic solution-blowing KW - Ultrafine nanofibers KW - van der Waals forces KW - Filtration theory ER - TY - JOUR TI - Theoretical and experimental investigation of physical mechanisms responsible for polymer nanofiber formation in solution blowing AU - Sinha-Ray, Sumit AU - Sinha-Ray, Suman AU - Yarin, Alexander L. AU - Pourdeyhimi, Behnam T2 - POLYMER AB - This work describes a comprehensive numerical model of solution blowing process of multiple three-dimensional polymer jets issued from a die nosepiece into a high-speed air flow and deposited onto a moving screen. The model solves the quasi-one-dimensional equations of the mechanics of free liquid jets with the jet axis configuration being three-dimensional. It accounts for the polymer solution viscoelasticity, jet interaction with the surrounding high-speed air flow, and solvent evaporation and jet solidification. The results include the polymer jet configurations in flight as well the detailed information on the pattern in which the oncoming polymer jets are deposited on the moving screen (the so-called lay-down), and its characteristics, in particular, the fiber-size distributions obtained under different conditions. The work also describes experiments on solution blowing and comparison of the numerical and experimental data. DA - 2015/1/15/ PY - 2015/1/15/ DO - 10.1016/j.polymer.2014.11.019 VL - 56 SP - 452-463 SN - 1873-2291 KW - Solution blowing KW - Nanofiber KW - Numerical modeling ER - TY - JOUR TI - Impact of aqueous suspension drops onto non-wettable porous membranes: Hydrodynamic focusing and penetration of nanoparticles AU - Sahu, R. P. AU - Sett, S. AU - Yarin, A. L. AU - Pourdeyhimi, B. T2 - COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS AB - The impacts and dynamic penetration of nanoparticle suspension drops into porous filter membranes are studied experimentally and theoretically. This type of penetration is associated with hydrodynamic focusing and is radically different from the wettability-driven imbibition. In the case of hydrodynamic focusing water can penetrate into a non-wettable porous medium at very low values of the dynamic pressure associated with drop impact. Two types of membranes are used in the experiments: (i) glass fiber filter membrane wettable by the carrier fluid (water), and (ii) polytetrafluoroethylene (PTFE) depth filter membrane, non-wettable by the carrier fluid. The nanoparticle entrainment and deposition inside the membrane bulk is used to mostly visualize the ultimate penetration fronts by observing the cut cross-sections of the membranes, albeit also provide an insight into innovative applications like circuit printing on nonwovens. The deposition patterns inside the membranes are also linked to the drop splashing patterns at their front surfaces. The experimental results confirm that during the dynamic focusing water can penetrate into a non-wettable porous medium (PTFE). Water also penetrates by the same hydrodynamic focusing mechanism into the wettable glass fiber membrane, where it additionally spreads on a much longer time scale due to the wettability-driven flow. A theory explaining hydrodynamic focusing penetration of liquid into porous medium after drop impact is proposed. It is used to explain and predict water penetration into the non-wettable filter medium after drop impact, and the results are compared with the experimental data. Also the critical thickness of non-wettable membranes determined by dissipation of the kinetic energy in flow inside membrane is evaluated and compared with the experimental data. DA - 2015/2/20/ PY - 2015/2/20/ DO - 10.1016/j.colsurfa.2014.11.023 VL - 467 SP - 31-45 SN - 1873-4359 KW - Drop impact KW - Hydrodynamic focusing KW - Penetration front KW - Nanoparticles KW - Coalescence filters ER - TY - JOUR TI - Biodegradable and biocompatible soy protein/polymer/adhesive sticky nano-textured interfacial membranes for prevention of esca fungi invasion into pruning cuts and wounds of vines AU - Sett, S. AU - Lee, M. W. AU - Weith, M. AU - Pourdeyhimi, B. AU - Yarin, A. L. T2 - JOURNAL OF MATERIALS CHEMISTRY B AB - Adhesive biodegradable membranes (patches) for the protection of pruning locations of plants from esca fungi attacks were developed using electrospun soy protein/polyvinyl alcohol and soy protein/polycaprolactone nanofibers. Several different water-soluble adhesives were either added directly to the electrospinning solutions or electrosprayed onto the as-spun nanofiber mats. The nanofibers were deposited onto a biodegradable rayon membrane, and are to be pressed onto the pruned location on a plant. The pore size in the nanofiber mats is sufficient for physically blocking fungi penetration, while the outside rayon membrane provides sufficient mechanical support in handling prior to deposition on a plant. Diseases like Vine Decline are one of the most important cases where such a remedy would be needed. It should be emphasized that these novel biodegradable and sticky patches are radically different from the ordinary electrospun ultra-filtration membranes. The normal and shear specific adhesive energy of the patches were measured, and the results show that they can withstand strong wind without being blown off. On the other hand, the patches possess sufficient porosity for plant breathing. DA - 2015/// PY - 2015/// DO - 10.1039/c4tb01887g VL - 3 IS - 10 SP - 2147-2162 SN - 2050-7518 ER - TY - JOUR TI - Reactive compatibilization of polyamide 6/polyethylene nonwoven based thermoplastic composites AU - Dasdemir, Mehmet AU - Maze, Benoit AU - Anantharamaiah, Nagendra AU - Pourdeyhimi, Behnam T2 - EUROPEAN POLYMER JOURNAL AB - The interface of polyamide 6/polyethylene (PA6/PE) was altered with compatibilizers in an effort to promote adhesion between PA6 reinforcement and PE matrix in nonwoven based thermoplastic composites. The compatibilizers chosen were triblock copolymer of styrene and ethylene/butylene (SEBS) and maleic anhydride (MA) functionalized SEBS with 1 wt% (SEBS-g-MA1) and 2 wt% (SEBS-g-MA2) MA contents. The interfacial adhesion in PA6/PE + Compatibilizer laminates was characterized using asymmetric double cantilever beam (ADCB) test. The effects of compatibilizer type, functional group content and concentration on the interfacial fracture toughness were determined. Also, the influence of lamination temperature and time on the interface enhancement was studied. After performing the compatibilization at composite fabrication stage, tensile responses of PA6/PE composites were greatly improved in the presence of functional compatibilizers. The best improvement on the overall tensile properties was achieved with SEBS-g-MA2 at the lowest compatibilizer concentration level of 2 wt%. The examination of fractured surfaces showed the clear evidence of the enhanced adhesion of matrix polymer to reinforcement fiber for the composites including SEBS-g-MA1 and SEBS-g-MA2. These results suggest that reactive compatibilization was achieved during composite fabrication stage and improved the adhesion between PA6 and PE resulting in a higher load transfer and better mechanical properties. DA - 2015/2// PY - 2015/2// DO - 10.1016/j.eurpolymj.2014.12.019 VL - 63 SP - 194-206 SN - 1873-1945 KW - Polyamide 6/polyethylene KW - Interface KW - Fiber/matrix bond KW - Bicomponent KW - Nonwovens KW - Thermoplastic composites ER - TY - JOUR TI - Preparation, Polymerization, and Performance Evaluation of Halogen-Free Radiation Curable Flame Retardant Monomers for Cotton Substrates AU - Edwards, Brian AU - Rudolf, Stacy AU - Hauser, Peter AU - El-Shafei, Ahmed T2 - INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH AB - Three halogen-free, phosphorus-based flame retardant monomers were synthesized with good yields and characterized using FT-IR, 1H NMR, and 31P NMR. Two of the monomers were novel phosphoramides and the third was derived from cyclotriphosphazene. Each monomer was coated onto cotton substrates with the aid of a UV flood curing system. The impacts of monomer concentration, photoinitiator concentration, UV exposure time and proximity of the specimen to the UV lamp on coating yield were evaluated by experiments designed with JMP Pro 10. Of the three monomers, the cyclotriphosphazene derivative was polymerized into a coating that was durable to Soxhlet extraction with acetone. Vertical burn testing showed that all three monomers are valuable flame retardants. These results agreed with thermogravimetric analysis findings that demonstrated quantitatively the effectiveness of each monomer at promoting char formation. For the cyclotriphosphazene derivative, the coating was easily visualized covering significant portions of the fabric using scanning electron microscopy. DA - 2015/1/21/ PY - 2015/1/21/ DO - 10.1021/ie502915t VL - 54 IS - 2 SP - 577-584 SN - 0888-5885 ER - TY - JOUR TI - Estimating Monomer Sequence Distributions in Tetrapolyacrylates AU - Caydamli, Yavuz AU - Ding, Yi AU - Joijode, Abhay AU - Li, Shanshan AU - Shen, Jialong AU - Zhu, Jiadeng AU - Tonelli, Alan E. T2 - MACROMOLECULES AB - Recently Ting et al. [ACS Macro Lett. 2013, 2, 770−774] described the syntheses of acrylic tetrapolymers with controlled molecular weights and tetramonomer compositions. Relative reactivity ratios of all monomer pairs were determined and used in the Walling–Briggs terminal copolymerization model along with Skeist’s equations to address the expected compositional drift in the monomer feed ratios. The anticipated control of monomer incorporation based on this approach was verified experimentally on several tetrapolyacrylates synthesized by RAFT polymerization, which additionally controlled their molecular weights. Their “new and simple paradigm combining both predictive models provides complementary synthetic and predictive tools for designing macromolecular chemical architectures with hierarchical control over spatially dependent structure–property relationships for complex applications” is extended here to the derivation of expected monad compositions, and diad, triad, and tetrad monomer sequence distributions. These were obtained directly from the comonomer reactivity ratios determined experimentally by Ting et al. Our motivation was twofold: (i) The similar chemical structures of the four acrylate monomers they selected (methyl, 2-carboxyethyl, 2-hydroxypropyl, and 2-propylacetyl acrylate) render the experimental determination of sequence distributions in the resulting tetrapolyacrylates problematic. (ii) Because they are spatially dependent structural parameters, the sequence distributions of monomer diads, triads, tetrads, etc., in co-, tri-, tetrapolymers, etc., are generally expected to correlate more closely with their properties than their overall compositions. DA - 2015/1/13/ PY - 2015/1/13/ DO - 10.1021/ma5019268 VL - 48 IS - 1 SP - 58-63 SN - 1520-5835 ER - TY - JOUR TI - Mechanical analysis of bi-component-fibre nonwovens: Finite-element strategy AU - Farukh, Farukh AU - Demirci, Emrah AU - Sabuncuoglu, Baris AU - Acar, Memis AU - Pourdeyhimi, Behnam AU - Silberschmidt, Vadim V. T2 - COMPOSITES PART B-ENGINEERING AB - In thermally bonded bi-component fibre nonwovens, a significant contribution is made by bond points in defining their mechanical behaviour formed as a result of their manufacture. Bond points are composite regions with a sheath material reinforced by a network of fibres’ cores. These composite regions are connected by bi-component fibres — a discontinuous domain of the material. Microstructural and mechanical characterization of this material was carried out with experimental and numerical modelling techniques. Two numerical modelling strategies were implemented: (i) traditional finite element (FE) and (ii) a new parametric discrete phase FE model to elucidate the mechanical behaviour and underlying mechanisms involved in deformation of these materials. In FE models the studied nonwoven material was treated as an assembly of two regions having distinct microstructure and mechanical properties: fibre matrix and bond points. The former is composed of randomly oriented core/sheath fibres acting as load-transfer link between composite bond points. Randomness of material’s microstructure was introduced in terms of orientation distribution function (ODF). The ODF was obtained by analysing the data acquired with scanning electron microscopy (SEM) and X-ray micro computed tomography (CT). Bond points were treated as a deformable two-phase composite. An in-house algorithm was used to calculate anisotropic material properties of composite bond points based on properties of constituent fibres and manufacturing parameters such as the planar density, core/sheath ratio and fibre diameter. Individual fibres connecting the composite bond points were modelled in the discrete phase model directly according to their orientation distribution. The developed models were validated by comparing numerical results with experimental tensile test data, demonstrating that the proposed approach is highly suitable for prediction of complex deformation mechanisms, mechanical performance and structure-properties relationships of composites. DA - 2015/1// PY - 2015/1// DO - 10.1016/j.compositesb.2014.09.003 VL - 68 SP - 327-335 SN - 1879-1069 KW - Fabrics/textiles KW - Fibres KW - Mechanical properties KW - Finite element analysis (FEA) ER -