Morphology Properties Of Poly Research Articles

Mechanical, thermal, and morphological properties of poly(3-hydroxy butyrate) nanocomposites prepared by melt mixing method

Abstract This research focuses on the preparation of poly (3-hydroxy butyrate) (PHB) nanocomposites using the melt mixing method. Two types of organically modified nanoclay, Cloisite 93A (C93A), and Cloisite 30B (C30B), were incorporated at various weight percentages into the PHB matrix to create the nanocomposites. Comparative analyses were conducted between PHB/C93A and PHB/C30B to assess their tensile and impact properties in relation to the matrix polymer. Between the nanocomposites, the PHB/C93A nanocomposites shows an optimum tensile modulus of 949 Mpa with a 3 wt% clay loading, while PHB/C30B nanocomposites demonstrated improved percentage elongation at break of 5.33 % and enhanced Izod impact strength of 39.67 J/m at 3 wt% of clay load. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) signifies the thermal behavior of both the matrix and nanocomposite. The degree of crystallinity is observed to be 47 % in case of the PHB/C30B nanocomposites as compared to the PHB/C93A nanocomposites as 38 %. Again in case of thermogravimetric analysis (TGA), the maximum % char of 5.198 is observed for the PHB/C30B nanocomposites. The enhanced viscoelastic behavior of the PHB/C93A nanocomposites was attributed at a peak of approx. 55–60 °C due to the incorporation of C93A nanoclay into the matrix in the study of dynamic mechanical analysis (DMA). The morphological investigation using WAXD analysis showcased particle clay intercalation and dispersion within the PHB matrix, indicating effective clay-matrix interactions. Overall, this study sheds light on the enhanced properties of PHB nanocomposites with the incorporation of organoclay, offering potential applications in various industries.

The Effect of Mechanical Recycling on the Thermal, Mechanical, and Chemical Properties of Poly (Butylene Adipate-Co-Terephthalate) (PBAT), Poly (Butylene Succinate) (PBS), Poly (Lactic Acid) (PLA), PBAT-PBS Blend and PBAT-TPS Biocomposite

AbstractMechanical recycling of plastics is regarded as the best option to minimize plastic waste pollution in the environment as it is well established and offers valorisation of plastics; however, there is limited research on the mechanical recyclability of biopolymers. This work aimed to evaluate the effect of multiple reprocessing on the mechanical, thermal, physical, chemical, and morphological properties of poly (butylene adipate-co-terephthalate) (PBAT), poly (butylene succinate) (PBS), poly (lactic acid) (PLA), PBAT-PBS blend, and PBAT-thermoplastic starch (TPS) composite. Low-density polyethylene (LDPE), a conventional non-biodegradable plastic, was also reprocessed for comparison studies. The biopolymers were extruded seven times in a twin-screw extruder and injection moulded into test specimens. Their properties were investigated at each extrusion cycle. Tensile, impact strength, and melt flow index (MFI) results of neat PBAT and PBAT-TPS were stable with slight changes throughout the seven reprocessing cycles and were comparable to LDPE. The properties of PBS, PLA, and PBAT-PBS blend, on the other hand, started to decrease after the second melt extrusion cycle. In addition, differential scanning calorimetry (DSC), thermogravimetry (TGA), and dynamic mechanical analysis (DMA) results showed that LDPE, PBAT, and PBAT-TPS exhibited better thermal and mechanical stability as compared to PBS, PLA, and PBAT-PBS blend. The FTIR spectroscopy results showed that the characteristic peaks of C=O and C–O around 1710 cm−1 and 1046–1100 cm−1 for PBS, PLA, and PBAT-PBS decreased due to multiple thermal processing, while those of PBAT and PBAT-TPS were unaffected. Scanning electron microscopy (SEM) micrographs of the fractured cross-sectional surface of PBS, PLA, and PBAT-PBS tensile specimens clearly evidenced the degradation of the biopolymers by severely fractured morphology as a result multiple reprocessing cycle. The results demonstrate that the fully biodegradable PBAT and PBAT-TPS can be mechanically recycled for at least seven cycles, and therefore, the service life of biodegradable polymers can be extended, and it is comparable with petroleum-based plastic. Graphical Abstract

Mechanical, thermal, and morphological properties of poly(lactic acid) (PLA)/ recycled tyre rubber waste compatibilised with chain extender

The accumulation of waste tires in our society is a pressing issue due to their short lifespan and increasing demand. This research delves into effective methods for recycling waste tires, with a particular focus on utilizing biopolymers. Polylactic acid (PLA), a completely biodegradable polymer, has gained popularity for its biocompatibility, biodegradability, mechanical strength, and ease of processing. To overcome its toughness and thermal stability limitations, PLA has been blended with commercial polymers, such as rubber. Furthermore, the incorporation of recycled tire waste into PLA has demonstrated the potential to enhance its durability and strength. Joncryl® ADR is used as a chain extender and reactive compatibilizer to enhance the chemical interactions in the binary blend. The samples were prepared using a twin-screw extruder with the temperature between 150 and 190 ºC and 60 rpm of screw speed. These blends are then analyzed using a range of characterization techniques, including Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), tensile testing, and notched Izod impact testing. The blends were then characterized by chemical changes, thermal transitions, and thermal degradation. it was found that the 90/10/0.6 (PLA/RW/ADR) nanocomposite exhibited maximum thermal degradation.

Physical, mechanical, viscoelastic, and morphological properties of poly(lactic acid)/ethylene‐co‐vinyl acetate blend reinforced with silicon carbide nanoparticles

AbstractPhase morphology, mechanical properties, melting and crystallinity, as well as the dynamic viscoelastic properties of poly(lactic acid) (PLA)/ethylene‐co‐vinyl acetate (EVA) (80/20) blend containing 0–3 wt% nano‐silicon carbide (SiC) were studied. Morphological observations revealed the localization of nano‐SiC particles around the EVA droplets with the consequence of a fall in the size of EVA dispersed phase in the nanocomposites compared with the unfilled blends. The mechanical characterization results showed a gradual increase in the elastic moduli and yield stress with increasing nano‐SiC content in the nanocomposites, while the strain at break and Izod impact strength were steadily decreased. The nano‐SiC particles served as nucleating agents for crystallization of the PLA matrix from the molten state. The crystallinity of the PLA matrix in the nanocomposites was slightly reduced compared with that of the unfilled blend. The dynamic mechanical thermal analysis results showed a gradual increase in the glass transition temperature of PLA matrix together with a steady decline of damping capability as the nano‐SiC content in the nanocomposite was increased. The dynamic rheological data demonstrated enhanced complex viscosities and storage moduli of the nanocomposites in a direct proportion to the nanofiller loading, specially at the low‐frequency region. The changes occurred in the various properties of the fabricated nanocomposites were interpreted in terms of alteration in the phase morphology and the physical interactions of the nano‐SiC particles with the blend's components.

Effects of Post-UV-Curing on the Flexural and Absorptive Behaviour of FDM-3D-Printed Poly(lactic acid) Parts

In this study, the effects of the post-ultraviolet-curing process on the flexural, absorptive, and morphological properties of poly(lactic acid) specimens produced using a fused deposition modelling technique 3D printer were experimentally investigated. In this direction, 15, 30, 45, and 60 min post-UV-curing processes were applied to poly(lactic acid) three-point bending and absorption specimens produced at 190 and 200 °C. Three-point bending tests and morphological analyses were applied after the post-ultraviolet-curing process, and absorption tests were applied by immersing the post-ultraviolet-cured specimens in a distilled water bath for 1-, 3-day, and 1-, 2-, and 4-week exposure times. The changes in flexural strain properties for each experimental parameter were also simulated by the computer-aided finite element analysis and compared with the experimental results. It was observed that the post-ultraviolet-curing process increased the flexural strength of the poly(lactic acid) specimens produced at both 190 and 200 °C with the same increasing trend up to 30 min of exposure, and the most significant increase was determined in the specimens that were subjected to post-ultraviolet-curing for 30 min. Although the flexural strengths of the post-ultraviolet-cured specimens were higher than the non-cured specimens in all conditions, it was detected that they tended to decrease after 30 min.

Mechanical and Morphological Characterizations of Laminated Object Manufactured 3D Printed Biodegradable Poly(lactic)acid with Various Physical Configurations

Mechanical behavior of 3D-printed poly(lactic) acid material is an open topic for research on the reliability assessment of structures in marine and offshore industries. This article presents the mechanical and morphological properties of poly(lactic) acid specimens using the laminated object manufacturing technique. The effect was experimentally investigated on 3D-printed discs joined together to make a laminated test specimen. The specimen was prepared and tested under different infill patterns, viz. linear, triangular, and honeycomb structure, 50–90% infill density, and under varying disc thickness ranging from 3.4–5.6 mm. The maximum compressive strength of 42.47 MPa was attained for the laminated specimen with 70% infill, honeycomb pattern, and disc thickness of 3.4 mm (six discs), whereas the linear infill pattern has shown the least compressive performance of 22.40 MPa. The result of the study suggested that the honeycomb infill pattern with 90% infill density and six discs provides the optimum set of parameters for the 3D printing of PLA samples for maximization of compressive strength, especially for laminated object manufactured specimens. The Taguchi L9 orthogonal analysis (OA) suggested a significant influence on the infill pattern and the number of discs, contributing 51.60% and 48.29%, respectively, towards the compressive strength. Scanning Electron Microscopy (SEM) and toolmaker microscopic images have supported the observed experimental mechanical results for the laminated object manufactured specimens. The used technique of laminated object-manufactured components in the current study may have effective usage in marine and structural engineering fields.

Optical and morphological properties of poly(vinyl chloride)-nano-chitosan composites doped with TiO2 and Cr2O3 nanoparticles and their potential for solar energy applications

Optical and morphological properties of poly(vinyl chloride)-nano-chitosan composites doped with TiO2 and Cr2O3 nanoparticles and their potential for solar energy applications

Mechanical and morphological properties of poly(vinyl chloride) and linear low‐density polyethylene polymer blends

AbstractIn this article, nonpolar polyethylene with polar poly(vinyl chloride) is considered as a polymer–polymer mixture. Direct mixing of poly(vinyl chloride) and polyolefins leads to the formation of incompatible mixtures that have weak complex properties. To form this mixture, chlorinated polyethylene and a copolymer of polyvinyl chloride with polyethylene were used as compatibilizers. An extreme relationship of the elastic modulus on the composition of the blend at a PE content (5–20 wt.%) was revealed. The use of EBM model representations made it possible to identify the reasons for this relationship, namely, the cumulative contribution of structural changes in PVC and the enhancement of interfacial adhesion due to the presence of a compatibilizer at the phase boundary.

Mechanical, Thermal and Morphological Properties of Poly(Lactic Acid) and Poly(Butylene Adipate-co-Terephthalate) Blends with Organoclay

This work studied the effect of nanoclay surface modified with 25-30 wt% of methyl dihydroxyethyl hydrogenated tallow ammonium (Clay-DHA) on morphological, mechanical and thermal properties of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends. The PLA/PBAT (75/25 w/w) blends without and with Clay-DHA were melt mixed by an internal mixer and molded by compression method. The morphological analysis observed the phase separation of PLA/PBAT blends due to minor PBAT phase dispersed as spherical shape in PLA phase, indicating a poor interfacial adhesion between PLA and PBAT phases. The incorporation of Clay-DHA could improve the compatibility of polymer blends. The tensile testing found that the addition of Clay-DHA 1 and 3 phr increased Young’s modulus of PLA/PBAT blends. The addition of Clay-DHA decreased the strain at break of PLA/PBAT blends. The thermal degradation of PLA/PBAT blends and composites showed the similar thermal degradation process step. The addition of Clay-DHA was no effect on thermal stability and thermal properties of PLA/PBAT blends.

Effect of nanoclay on mechanical and morphological properties of poly(lactide) acid (PLA) and polypropylene (PP) blends

The aim of this study is to blend the poly(lactide) acid (PLA) and polypropylene (PP) with a fixed ratio of PLA to PP, 75 to 25% by weight using the twin screw extruder. A 3 wt% MAgPP was added into the polymer blends as a compatibilizer. Organo-nanoclay of montmorillonite (OMMT), were added in the amounts of 1, 3, 5 and 7 wt% in polymer blends to improve the mechanical, thermal and morphological properties of the nanocomposites. The resulting polymer nanocomposites were evaluated by using universal testing machine, Izod impact test, thermogravimetric analyzer (TGA) and scanning electron microscope (SEM). The nanocomposites with 1 wt% nanoclay showed the highest tensile strength results which is 49.53 MPa. The Izod impact strength was increased up to 39.2% for 3 wt% of nanoclay. The tensile strain increased about 9.4% after addition of 1 wt% of nanoclay as compared with PLA/PP blend without nanoclay. Overall tensile strain results show that there were slightly changes was observed as increasing the nanoclay content from 3 to 5 and 7 wt%. TGA results showed that the degradation temperature was improved by the addition of 5 wt% of nanoclay in PLA/PP blend. The brittle fractured surface was observed under SEM analysis when 5 wt% nanoclay used. In general, mechanical properties reduced as the nanoclay content increased.

Comparison of thermal, structural and morphological properties of poly(L-lactide) and poly(L-lactide)/hydroxyapatite microspheres for laser sintering processes

A comparison of poly(l-lactide) (PLLA) and poly(l-lactide)/hydroxyapatite (PLLA/HAp) biocomposite microspheres fabricated by emulsion solvent evaporation technique designed for laser sintering (LS) applications is presented. Key properties such as thermal and structural as well as geometry, size distribution and powder flowability, which are crucial for this technique, are characterized to validate the applicability of microspheres for LS. The biocomposite microspheres turns out to be more suitable for the LS process than PLLA due to the higher thermal stability, broader sintering window and higher powder flowability.

Thermal and Morphological Properties of Poly(L-Lactic Acid)/Poly(D-Lactic Acid)-B-Polycaprolactone Diblock Copolymer Blends.

Due to the brittle nature of poly(lactic acid) many attempts have been made to flexibilize this polyester for applications such as thin films and foils. However, due to complex phase behavior, many drawbacks for plasticizer and blend components are described. To overcome miscibility, post crystallization and migration issues a principle of click-chemistry was employed to change the molecular characteristics from external to internal plasticization by fixation of a plastisizing unit with help of a stereocomplex crystallization. Hydroxyl terminated polycaprolactone oligomers were used as a macroinitiator for the ring opening polymerization of d-lactide, resulting in blockcopolymers with plasticizing unit polycaprolactone and compatibilizing poly(d-lactic acid)-blocks. The generated block copolymers were blended with a poly(l-lactic acid)-matrix and formed so called stereocomplex crystals. In comparison to unbound polycaprolactone the polycaprolactone blocks show a lower migration tendency regarding a solution test in toluene. Besides that, trapping the plasticizing units via stereocomplex also improves the efficiency of the plasticizer. In comparison to polymer blends with the same amount of non-bonded polycaprolactone oligomers of the same molecular weight, block copolymers with poly(d-lactic acid) and polycaprolactone can shift the glass transition temperature to lower values. This effect can be explained by the modulated crystallization of the polycaprolactone-blocks trapped into the matrix, so that a higher effective amount can interact with the poly(l-lactic acid)-matrix.

Influence of Boswellic acid on physical, structural and morphological properties of poly (vinyl alcohol) films

Abstract In the present study Poly(vinyl alcohol) (PVA)/Boswellic acid (BA) (PBA) films were fabricated by solvent casting method with different weight percentage of BA. Physicochemical and mechanical properties of the PBA films were studied using FTIR, XRD, SEM and UTM techniques. Moisture absorption, degree of swelling, water vapor (WVP) and oxygen permeability (OP) of the PBA films were also investigated. Results indicated that moisture absorption and degree of swelling of PBA films were increased with increase of BA content. The FTIR study confirmed the intermolecular interaction between functional groups of PVA and BA in the films. Uniform homogeneous morphology of PBA films suggested miscibility and compatibility between PVA and BA. From the mechanical results, PBA-2 film was found to have the best tensile strength of 32.06±0.10 MPa and elongation at break of 161.23±0.10%. The result of water contact angle measurements revealed that PBA films were hydrophilic in nature while XRD patterns suggest the contracted crystallinity of the film. PBA films with added BA showed improved barrier properties against WVP and OP. Furthermore, the prepared active films do not deteriorate the thermal properties after incorporation of BA. With all of these improved results, it was concluded that PBA films can be used for food packaging applications.

The effects of initiators mixture on suspension polymerization of vinyl chloride and its comparison with other productivity-enhancing procedures

Molecular and morphological properties of poly(vinyl chloride) (PVC) grains produced by suspension polymerization of VCM in the presence of a mixture of fast, mild and slow initiators (named as Cok process) was experimentally investigated in a pilot-scale reactor. In contrast to nonisothermal and fast initiator dosage process, using initiators mixture has the smallest influence on molecular weight and polydispersity index compared to the control process. It is found that Cok-PVC grains have the lowest cold plasticizer absorption and porosity among productivity-enhancing processes. Scanning electron microscopy showed that the particles produced by Cok process are more regularly shaped, with a smoother surface compared with the control resin. All three productivity-enhancing techniques lead to an apparent quality enhancement, higher flowability and greater bulk density of final grains when compared with control resin grains. While both nonisothermal and fast initiator dosage polymerization process broaden the particle size distribution (PID) of final PVC grains, applying Cok process produces particles with the same PID as a control process. In comparison with nonisothermal trajectory and continuous fast initiator dosage system, the Cok polymerization process leads to the most delay of motionless conversions, fusion time and the formation of a three-dimensional skeleton of primary particles as well.

Mechanical, thermal and morphological properties of poly(lactic acid) by using star-shaped poly(ε-caprolactone) with POSS core

Polyhedral oligomeric silsesquoxane (POSS) cored star-shaped poly(ε-caprolactone) (PCL) polymers (POSS-(PCL)8, SP) were prepared via combination “click” chemistry and ring-opening polymerization (ROP). Then, these star-shaped polymers were melt-blended with commercial linear poly(lactic acid) (PLA) by using laboratory scale twin screw extruder to enhance some of the properties such as toughness of PLA. The thermal, mechanical, and morphological characters of the PLA/SPs were investigated as a function of SP type, i.e. star polymers having different molecular weight with different chain lengths (n = 10, 20, 30, and 50 repeating units) at constant PLA/SP ratio (90/10). The addition of SP enhanced some of the mechanical behavior of PLA. It was established that SP20 (n = 20) is the most appropriate SP-type for improving the mechanical properties of PLA. Also, 1,4-phenylene diisocyanate (PDI) as a compatibilizer was added to blends with constant amount (%1). It observed that PLA/SP blends have maximum effect on toughness of PLA with addition of PDI.

Effect of annealing on mechanical and morphological properties of Poly(L-lactic acid)/Hydroxyapatite composite as material for 3D printing of bone tissue growth stimulating implants

In this work, effect of additional annealing on mechanical and morphological properties of 3D-printed PLLA/HAp composite scaffolds of three compositions (12.5, 25, and 50 wt.% of HAp) was investigated. Morphology and Young’s modulus of 3D-printed scaffolds were investigated by scanning electron microscopy and nanoindentation. It has been shown that additional annealing does not have an effect on the homogeneous distribution of HAp powder in the PLLA-matrix. Results of nanoindentation showed growth of Young’s modulus after annealing. The maximum value of 9393 ± 709 MPa Young’s modulus was reached for the annealed composite with 50 wt.% of HAp.

Study on the Release of Quinine Sulfate from Polylactic Acid/Chitosan/Quinine Sulfate Composite Materials

Recently, the polylactic acid /chitosan composite has been used as a drug carrier to regulate the drug release aim to increase effective and decrease drug dosage. Polylactic acid/chitosan composite materials carry 10-50% quinine sulfate was prepared by the water/oil water method to study the release of quinine sulfate. Effects of quinine sulfate content, pH and kinetics of quinine sulphate release were investigated. The results showed that polyacid/chitosan composite materials with high quinine sulfate content for slow speed of release quinine sulfate. The polylactic acid/chitosan composite materials carry 50% quinine sulfate is smallest speed of release quinine sulfate. In pH = 7.4 the release rate of quinine sulfate is greater than the pH = 2.0. The process of releasing quinine sulfate from polylactic acid/chitosan/quinine sulfate composites materials follows the Korsmeyer-Peppas kinetics model and diffuses following the Fick law.
 Keyword
 Release, composite materials, polyaxit lactic, chitosan, quinin sulfat
 References
 [1] Nguyễn Thúy Chinh, Nghiên cứu sự giải phóng thuốc nifedipin được mang bởi vật liệu tổ hợp poly axit lactic/chitosan, Luận án tiến sĩ hóa học, Hà Nội, (2016).[2] Silverajah V.S., Nor A.I., Norhazlin Z., Wan M., Wan Y. and Hazimah A.H., Mechanical, thermal and morphological properties of poly (lactic acid)/ epoxidized palm olein blend, Molecules, 17, 11729, (2012). [3] Gavhane Yogeshkumar N., Gurav Atul S. and Yadav Adhikrao V., Chitosan and its applications: A review of literature, International Journal of Research in Pharmaceutical and Biomedical Sciences, 4(1), pp. 312-331, (2013). [4] Harvie B.F., Poly-L-lactic acid (PLA) in surgery, Philosophy Doctor Thesis, Smith Nephew, First choice in Endoscopy, (2000).[5] Prabaharan M., Rodriguez - Perez M.A., de Saja J.A., Mano J.F., Preparation and characterization of poly (D,L-lactic acid)/ chitosan hybrid scaffold with drug release capability, J. Biomed Mater Res B Appl Biomater, 81(2), pp. 427-434, (2007).[6] Dev A., Binulal N.S., Anitha A., Nair S.V., Fruike T., Tamura H., Jayakumar R., Preparation of poly(lactic acide) nanopaticles for anti-HIV drug delivery applications, Carbohydrate Polymers, 80, pp. 833-838 (2010). [7] Nanda R., Sasmal A., Nayak P.L., Preparation and character-rization of chitosan-polylactide composites blended with Cloisite 30B for control release of the anticancer drug Paclitaxel, CarbohydratePolymers, 83, pp. 988-994, (2011).[8] Portero A., Remunan Lopez C., Vila-Jato J.L., Effect of chitosan and chitosan glutamate enhancing the dissolution properties of the 144 poorly water soluble drug nifedipine, International Journal of Pharmaceutics, 175, pp. 75–84, (1998).

Thermal, Mechanical, Viscoelastic and Morphological Properties of Poly(lactic acid) based Biocomposites with Potato Pulp Powder Treated with Waxes.

The thermal, mechanical and viscoelastic properties of biocomposites of poly(lactic acid) (PLA) with 20 wt.% of potato pulp powder were investigated. The potato pulp powder utilized is a byproduct from the production and extraction of starch. The results showed that the potato pulp powder does not act as reinforcement, but as filler for PLA, due to an unfavorable aspect ratio and the irregular shape of the particles. In order to improve the mechanical response of the PLA/potato pulp powder biocomposites, surface treatment of the potato pulp particles with bio-based and petroleum-based waxes was investigated. This treatment was found to improve the properties of the biocomposites, enhancing the adhesion between the PLA based polymeric matrix and the potato pulp fibers. The best result is obtained with a petroleum-based wax, but also the bio-based waxes lead to good mechanical properties of the biocomposite. Thus, the addition to PLA of potato pulp powder, treated with waxes, appears a method able to (i) utilize and valorize an abundant agro-food biomass such as potato pulp, according to the principles of circular economy, (ii) favor the production of articles with properties valuable for practical applications, and (iii) reduce the cost of the final products, considering the relatively high cost of PLA.

Effect of core–shell rubber toughening on mechanical, thermal, and morphological properties of poly(lactic acid)/multiwalled carbon nanotubes nanocomposites

ABSTRACTThe effect of core–shell rubber (CSR) toughening on mechanical and thermal properties of poly(lactic acid)/multiwalled carbon nanotubes (PLA/CNT) nanocomposites were investigated. The nanocomposites were prepared by direct melt blending method in a counter‐rotating twin‐screw extruder. The contents of CSR were varied between 5 and 20 wt % while the content of CNT was kept at 5 phr. The extruded samples were injection molded into the desired test specimens for mechanical and thermal properties analysis. The impact strength of PLA/CNT increased with increasing CSR content with concomitant decrease in tensile strength and modulus. Interestingly, the flexural strength increased at low CSR content before decreasing at 15 and 20% content. Differential scanning calorimetry analysis on the second heating cycle shows no crystallinity content for PLA/CNT and all CSR toughened PLA/CNT nanocomposites, while thermogravimetric analysis shows lower thermal degradation of all CSR toughened PLA/CNT as compared to PLA/CNT nanocomposite. This study reveals significant correlation between CSR loading with the mechanical and thermal properties of the nanocomposites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47756.

Thermoplastic poly(urethane-thiourethane) triblock copolymers with SWCNTs composite

Poly(urethane-thiourethane) triblock copolymer nanotube composites have been synthesized by reacting hexamethyl diisocyanate, polyethylene glycol, chain extended with two different diols 3,6-dioxa-1,8-octanedithiol (DODT), 3,7-dithia-1,9-nonanedithiol (DTDT) and different weight percentage of single-walled carbon nanotubes (SWCNTs). The structure of the triblock copolymers and nanocomposites were analyzed by Raman and DSC. Storage modulus (G′), loss modulus (G″) and viscoelastic properties of the nanocomposites were explored by dynamic mechanical analysis and melt viscosity was studied using parallel-plate rheometer. The nanotube composites were obtained as tough transparent films and are thermally stable at 450 °C, exhibiting glass transition temperatures at −65 °C for DODT based composites and −58 °C for DTDT based composites. The rheology and morphological properties of Poly(urethane-thiourethane) (PTU) composites of various composition are discussed. The sample PU-34-SH-CNT and PU-34 OSH-CNT exhibits high G′ value of 7000 MPa and 4000 MPa. Phase separation was observed in melt flow at high shear rate for both SH-CNT and OSH-CNT composites. These copolymer nanocomposites behave like a pseudoelastic, single-phase homopolymer melts and could be used in high temperature coating applications.