Polymer blends and composites polymerscienceandtechnologyii november18, 2015 the major problem in the application of polymersin engineeringistheirlowstiffness. Mechanochromic microfibers stabilized by polymer blending. The initial dye concentration has an effect on the initial emission ratio and on the relative shift of the emission from the excimer to the monomer bands. Mechanochromic lldpecyanoopv blends can be readily obtained by meltmixing, and aggregates are furnished through local phase separation upon cooling.
Rheology is a branch of physics that deals with the deformation and flow of matter under stress. Mechanochromic behavior of a luminescent silicone rubber. Function extension of dualmechanochromism of acylated. Color and shape reversible, recoverable and repeatable. Mechanochromic polymers a wellknown approach toward mechanochromic polymers relies on the incorporation of excimerforming fluorophores into a matrix polymer and. Three 2d luminescent isomeric porous coordination polymers are synthesized and characterized. An overview of the mechanoflurochromism of polymeric composite systems, including basal principle, preparation methods and mechanochromic mechanism, has been presented. On the other hand, biological motors have been estimated to exert forces of a few pn to tens of pn. Mechanochromic behavior of a luminescent elastomer under tensile deformation jimin ha, yeon ju kim, kwangun jeong, changwoon nah bk21 plus haptic polymer composite research team, department of polymer nano science and technology, chonbuk national university, jeonju 561756, republic of korea. Characterization of mechanically alloyed polymer blends for. The latter constitutes a mechanism that has been previously associated with mechanochromic response in different polymerdye blends crenshaw et al.
A photochromic polymer exhibiting mechanochromic behavior is prepared by means of ringopening polymerization rop of. Color changes in mechanochromic polyethylene blends. Upon large deformation of the polymeric structure, a shift of the fluorescence emission from the excimer band to the monomer band is observed, due to reorganization of dye aggregates. Polymer blends, volume 1 highlights the importance of polymer blends as a major new branch of macromolecular science. Request pdf deformationinduced color changes in mechanochromic polyethylene. It was particularly found that blends of the water. The mechanochromic response of the synthesized polymer is fast.
The objective of polymer blending is a practical one of achieving commercially viable products through either unique properties or lower cost than some. The alkyl tails affect the solubility of the chromophores in the polymer matrix and lead to different aggregation properties. Mechanochromic polymers based on microencapsulated. A novel mechanochromic elastomer based on silicone rubber and coumarin 6 dye have been prepared with various concentrations of the dye ranges from 2wt. Recent approaches toward mechanochromic polymeric materials. A reversibly mechanochromic conjugated polymer request pdf. Facile design of pressuresensing color films of liquid. Bk21 plus haptic polymer composite research team, department of polymer nano. A simple and versatile concept to bestow polymers with mechanochromic behavior is the incorporation of dye. Mar 23, 2014 the term piezochromic polymer is often used as a synonym, but strictly speaking it defines the subset of mechanochromic materials that respond to pressure.
Polymer blends are physical mixtures of two or more polymers withwithout any chemical bonding between them. Mechanochromic polymer blends journal of materials chemistry. Ling jing jie darryl, lim bing wen, dr jiang ying, dr tan yong leng kelvin introduction this project aims to investigate the mechanochromic luminescence properties of different dyes and polymer blends that is. Function extension of dualmechanochromism of acylated hydroxypropyl cellulosesynthetic polymer composites achieved by moderate compatibility as well as hydrogen bonding. Polymer blends have been intensively studied because of their theoretical and practical importance. The latter constitutes a mechanism that has been previously associated with mechanochromic response in different polymer dye blends crenshaw et al. The central cc bonds in dabbf moieties can be cleaved by mechanical force to form the corresponding stable blue radicals, which can be quantitatively evaluated by electron paramagnetic. Chemical engineering 160260 polymer science and engineering. Approaches to polymeric mechanochromic materials core. In this paper, we report our preliminary findings on multicolor mechanochromic polymer blends that can discriminate between two different mechanical stimuli, i. Mechanochromic polymers, macromolecules, or their composites, which respond to mechanical stress with a change of their absorption and fluorescence features, have been previously considered to monitor the materials failure.
Lec1 introduction to polymer blend types of polymer blends. This feature has evoked a growing interest in the last decades, thanks to the progress of chromogenic molecules whose optical characteristics and chemical functionalities allow their effective insertion in many thermoplastic and thermoset matrices. Mechanochromic polymers are, in the strictest sense of the definition, macromolecular materials, which change their absorption color in response to mechanical action. To explore the mechanochromic behavior, we prepared blends of p3teot with the highly polar, watersoluble polymer pva. An ndendi system based on a mechanochromic fluorescent polymer coating on a part could fluoresce or glow in damaged. Mixture of two or more fractions of the same polymer each of which has different molecular weight distribution. Our polymer can detect the distortion or destruction of objects.
Visakh, in recent developments in polymer macro, micro and nano blends, 2017. Dai, cochair aditi chattopadhyay, cochair mary laura lind bin mu hongyu yu. Mechanochromic polymeric materials has attracted considerable interest in recently years due to their potential applications in detecting critical stress or recoding the mechanical history of polymer through direct optical measures. Ling jing jie darryl, lim bing wen, dr jiang ying, dr tan yong leng kelvin introduction this project aims to investigate the mechanochromic luminescence properties of different dyes and polymer blends that is the change in intensity andor colour. Polymer blend of two or more different semicrystalline polymers are miscible in the crystalline state as well as in the molten state. The possibility to directly visualize the buildup and release of forces in synthetic polymers at the molecular level has important implications for materials science. Various examples are reported of chromogenic materials composed of a functional dye covalently linked to the polyme mechanoresponsive materials. Stress sensing in polycaprolactone films via an embedded. Approaches to polymeric mechanochromic materials wiley online. Azobenzene chromophores were introduced into a copolyamide oligomer to provide conformational latches which stabilized thecisazobenzenes by the formation of intramolecular hydrogen bonds. Mechanochromic polymers, classified by polymers respond optically to mechanical stimuli, have. Polymer blends, volume 2 aims to show the importance of mixed polymer systems as a major branch of macromolecular science and provides a broad background of principles and practices in this field. The central cc bonds in dabbf moieties can be cleaved by mechanical force to form the corresponding stable blue radicals, which can be. The outstanding benefit of processing microfibers from polymer blends is the ease of obtaining structurally stable, selfreporting material with longer durability.
Chapter 5 mechanochromic fluorescent materials rsc publishing. Polymer blends and composites from renewable resources objectives. Kander department of materials science and engineering, virginia polytechnic institute and state university, blacksburg, va 240610237, usa. Chapter 5 mechanochromic fluorescent materials rsc. Mechanochromic fluorescent or mechanofluorochromic materials change their emission colours spectra when an appropriate external mechanical force stimulus is applied. The use of the term polymer alloy for a polymer blend is discouraged, as the former term includes multiphase copolymers but excludes incompatible polymer blends. First, we prepared blends with a content of p3teot of 1. Mechanochromic polymers are defined as materials that are able to detect a mechanical stress through an optical output. Polymer as an important component of blends and composites with liquid crystals. Unlike triboluminescence which does not require additional excitation source other than force itself, ml is often manifested by external photoexcitation such as a uv lamp. The book begins by introducing polymer blends, describing thermodynamics, miscibility, and phase separation, and.
Abstract we have designed an inexpensive and sensitive mechanochromic system. Us12693,801 20070727 20100126 selfassessing mechanochromic materials active us8236914b2 en. Uv vis spectra for the synthesized compounds and polymers pdf. Notably, cyanosubstituted distyrylbenzenepmma blend films with a. Preparation of a mechanochromic elastomer using liquid. While tailored blends with such chromophorecontaining polymers can be readily prepared, aggregate formation and stresstransfer to the aggregates can be. The rational design and blending of two mechanochromic polymers. Starting from where the first volume left off, the book covers topics in the area of polymer blends in chapters 1123. Mechanochromic fluorescent polymers with aggregation. Mechanochromic polymers, which react to mechanical force by changing color, are expected to find applications in smart materials such as damage sensors. Mechanochromic polymer blends journal of materials. Otsukamulticolor mechanochromic polymer blends that can discriminate between stretching and. Polymers with a mechanochromic response chemviews magazine.
Dec, 2017 the mechanochromic response of the synthesized polymer is fast. Mechanochromic polymers, that is, polymers sensitive to mechanical impact, promise great potential for applications in damage sensors. By the end of this course, the students should be able to. Mechanoresponsive, luminescent polymer blends based on an. Samantha burns university of pennsylvania, materials engineering and statistics, sunfest fellow. We have developed a facile method for material design of pressuresensing films for various operating temperatures using cholesteric liquid crystalline chlc cellulose derivatives. All of these inventors knew each other, two were brothers c. Deformationinduced color changes in mechanochromic. Stainrate dependence of deformation in polymer dispersed liquidcrystal materials. Polymer inorganic composites with diarylbibenzofuranone dabbf moieties, dynamic covalent mechanochromophores, were prepared, and their mechanochromic behavior was systematically investigated. In the field of material science, one major problem of structural polymers is failure through mechanical stress or strain. Mar 15, 2017 research at the university of connecticuts department of chemical and biomechanical engineering and department of mechanical engineering has yielded polymerbased mechanochromic devices that can become transparent or change color in response to mechanical force. A mechanochromic material includes a polymer having a backbone containing a mechanophore.
Luminescent mechanochromic sensors based on polyvinylidene. The microfibers also showed reversible photochromism upon irradiation with ultraviolet uv light 360370 nm and green light 520530 nm. In this study, a mechanochromic elastomer was prepared by physically dispersing dye materials into a rubber matrix by solution mixing technique. Characterization of mechanically alloyed polymer blends for selective laser sintering julie p. Mechanochromic behavior of a luminescent elastomer. Investigating the mechanochromic properties of elastomers authors. A quantitative difference exists for the mechanochromic response of blends comprising the higher density pe95 or pe94, which both exhibit thick crystalline lamellae, and the lower density pe92 or pe90, in which the lamellae are much thinner and less abundant.
Uconn research yields polymer mechanochromic devices. The copolyamide oligomer was chemically inserted into a polyurethane copolymer. The combination of the properties of the blend components can often result in drastic differences in the material chromogenic responsiveness. Polymer melts, polymer blends, miscible polymer blends, immiscible polymer blends, compatibilization, rheological properties and phase structures. The gibbs free energy of mixing for a polymer blend is given by strobl p. Material systems based on mechanochromic molecules are finding applications as dynamic functional materials, sensors, and logic gates. Plaldpe blends were prepared using a laboratory scale single screw extruder and characterized in terms of the rheological properties. For aggregachromic polymer blends, more force is needed towards the unentangling of the macromolecular matrix. Polymer blends are physical mixtures of two or more polymers. Because the number of mechanoflurochromic covalently tethered dye polymers are very limited at present, the development of the dyedoped polymer composite systems seems to be of. More broadly defined, polymeric materials that change their emission or reflection color are also included.
Mechanochromic behavior of a luminescent elastomer under. Mechanochromic fluorescence in epoxy as a detection method. However, shape memory polymers maintain their original shapes because of the balance of switching segment and netpoint after a. Stretch release the fluorescent polymers were synthesized with monomers and fluorescent substance as a crosslinking unit. Topics range from polymerpolymer compatibility and the statistical thermodynamics of polymer blends to the phase separation behavior of polymerpolymer mixtures, transport phenomena in polymer blends, and mechanical properties of multiphase polymer blends. Mechanochromic fluorescent materials introduces the reader to the concept of. Micro and nano scale phase morphologies, interphase characterization and properties offers a comprehensive approach to the use of compatibilizers in polymer blends, examining both fundamental and advanced knowledge in the field. Development of mechanochemically active polymers for. Polymerinorganic composites with diarylbibenzofuranone dabbf moieties, dynamic covalent mechanochromophores, were prepared, and their mechanochromic behavior was systematically investigated. Second, biologists would like to understand specific mechanical triggers in biological systems, while bulk mechanochromic systems. Mechanochromic polymers are defined as materials that are. Visualization of material distortion on bridges and tunnels fluorescent substance unstretched region blue fluorescence stretched region green fluorescence strain and fluorescence spectral change fluorophore as crosslinking structure.
This work combined mechanochromism and loadinduced chemical reaction, and the dual mechanochromic polymer may have potential applications in damagesensing and loadtriggered selfstrengthening. Mechanochromic polymers, which react to mechanical force by changing. Oligopphenylene vinylene excimers as molecular probes. Polymer blend pb a mixture of at least two polymers or copolymers.
Introduction the visualization of mechanical stresses in polymeric materials by optical changes is useful for a broad range of applications that range from structural health monitoring. Because the number of mechanoflurochromic covalently tethered dyepolymers are very limited at present, the development of the dyedoped polymer composite systems seems to be of. Mechanochromic polymers develop their color when the stretching force leads the mechanophores to change their molecular structure or configuration. Us8236914b2 selfassessing mechanochromic materials. Multicolor mechanochromic polymer blends that can discriminate between stretching and grinding kuniaki ishizuki department of chemical science and engineering, tokyo institute of technology, 2121 ookayama, meguroku, tokyo 1528550, japan. Preparation of a mechanochromic elastomer using liquid crystal dispersed in polymer. Development of mechanochemically active polymers for early damage detection by jin zou a dissertation presented in partial fulfillment of the requirements for the degree doctor of philosophy approved november 2014 by the graduate supervisory committee. Their luminescence properties can be modified by grinding and they can act as mechanochromic materials and their properties are probably related to the weak interactions of cuprophilicity and. Although numerous types of mechanochromic polymers have been reported so far, developing mechanochromic polymers that can recognize different mechanical stimuli remains a formidable challenge.
Multicolor mechanochromic polymer blends that can discriminate. On the other hand, biological motors have been estimated to exert forces of a few pn to tens of pn 90. Investigating the mechanochromic properties of elastomers. Multicolor mechanochromic polymer blends that can discriminate between stretching and grinding acs macro letters. Mechanochromic luminescence ml references to intensity andor color changes of solidstate luminescent materials induced by mechanical forces, such as rubbing, crushing, pressing, shearing, or smearing. A mechanochromic composite comprises an excimerforming fluorescent dye dispersed in a compatible polymeric host. Luminescent mechanochromic porous coordination polymers. This is an important group of materials with a huge range of applications, including use in sensors, memory chips, security inks, and light devices. In this case, one glass transition temperature will be observed. State of the art, new challenges, and opportunities jyotishkumar parameswaranpillai, sabu thomas, and yves grohens 1. From the rearrangement of molecules to bond rupture, up to nns of force is required 18.
The most important characteristic of a polymer blend of two or more polymers is the phase behavior. A mechanochromic polyurethane elastomer was synthesized and demonstrated. Chemical engineering 160260 polymer science and engineering lecture 11 polymer blends february 9, 2001. Various examples are reported of chromogenic materials composed of a functional dye covalently linked to the polymer chains. Remarkable mechanochromism in blends of a conjugated. Reported fluorescent polymer that shows a reversible color change takes 2 hours to be restored. A polymer blend nanocomposite can be defined as a polymer nanofiller system in which the inorganic filler is on a nanometric scale at least in one dimension and it can be a polymer. Such works are very important in the development of composites and blends from biodegradable polyesters. P3teot was incorporated into the pva matrix by mixing the aqueous solutions of both polymers. A series of acetylated hydroxypropyl celluloses ahpcs with different degrees of acetylation dsac was prepared and their concentrated solutions in monomeric solvents showed coloration based on the.
These blends were used to fabricate luminogenic mechanochromic thin. Us8236914b2 us12693,801 us69380110a us8236914b2 us 8236914 b2 us8236914 b2 us 8236914b2 us 69380110 a us69380110 a us 69380110a us 8236914 b2 us8236914 b2 us 8236914b2 authority us united states prior art keywords polymer mechanophore stress spiropyran polymethacrylate prior art date 20070727 legal status the legal status is an assumption and is not. No attention has been given in the past to rheological characterization of plaldpe polymer blends. In these blends, we observed that a significant portion of the chromophores aggregated immediately upon. Mechanochromic fluorescent materials rsc publishing.
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