Thermal Stability Of Blends Research Articles

Crystallization, thermal, and compatibility performances of poly (butylene succinate) (PBS)/poly((R)‐3‐hydroxybutyrate‐co‐(R) 3‐hydroxyhexanoate) (PHBHHx) blends

AbstractBiodegradable materials provide protective properties comparable to conventional plastics while diminishing reliance on nonrenewable resources. Environmentally friendly polymer blends were prepared by melting poly(R)‐3‐hydroxybutyrate‐co‐(R)‐3‐hydroxyhexanoate) (PHBHHx) with poly (butylene succinate) (PBS). PBS was synthesized through esterification and polycondensation using 1,4‐butanediol and succinic acid, with tetrabutyltitanate as the catalyst. The PHBHHx is supplied by Bulepha®PHA Company of China, model number BP330. The effects of PHBHHx content on thermal behavior, compatibility, and thermal stability of PBS/PHBHHx blends were systematically investigated. Differential scanning calorimetry (DSC) results indicated that the addition of PHBHHx influenced the crystallization behavior, the crystallization temperature (Tc) of PBS decreased meanwhile, the crystallization half‐time of PBS is reduced to 1.5 min compared with neat PBS (5 min) after isothermal is crystallized at 95°C. Polarized Optical Microscopy (POM) images also revealed that crystallization rate accelerated in the blend with increasing PHBHHx content. Rheological and Scanning Electron Microscopy (SEM) analysis demonstrated that incorporating a significant content of PHBHHx reduced compatibility between PBS and PHBHHx. Mechanical property testing indicates that the addition of PHBHHx reduced the toughness of blends. Additionally, the addition of a small amount of PHBHHx imparts a higher crystallinity (56%) and heat resistance of the PBS/PHBHHx blends (78°C) was higher than neat PBS (74°C).Highlights Laboratory synthesis of high molecular weight PBS. Optimal ratios improved crystallinity and thermal stability of blends. A systematic study of the crystallization properties of blends.

Comprehensive Investigation into the Impact of Degradation of Recycled Polyethylene and Recycled Polypropylene on the Thermo-Mechanical Characteristics and Thermal Stability of Blends.

The impact of degradation on plastics is a critical factor influencing their properties and behavior, particularly evident in polyethylene (PE) and polypropylene (PP) and their blends. However, the effect of photoaging and thermal degradation, specifically within recycled polyethylene (rPE) and recycled polypropylene (rPP), on the thermo-mechanical and thermostability aspects of these blends remains unexplored. To address this gap, a range of materials, including virgin polyethylene (vPE), recycled polyethylene (rPE), virgin polypropylene (vPP), recycled polypropylene (rPP), and their blends with different ratios, were comprehensively investigated. Through a systematic assessment encompassing variables such as melting flow index (MFI), functional groups, mechanical traits, crystallization behavior, microscopic morphology, and thermostability, it was found that thermo-oxidative degradation generated hydroxyl and carboxyl functional groups in rPE and rPP. Optimal mechanical properties were achieved with a 6:4 mass ratio of rPE to rPP, as validated by FTIR spectroscopy and microscopic morphology. By establishing the chemical model, the changes in the system with an rPE-rPP ratio of 6:4 and 8:2 were monitored by the molecular simulation method. When the rPE-rPP ratio was 6:4, the system's energy was lower, and the number of hydrogen bonds was higher, which also confirmed the above experimental results. Differential scanning calorimetry revealed an increased crystallization temperature in rPE, a reduced crystallization peak area in rPP, and a diminished crystallization capacity in rPE/rPP blends, with rPP exerting a pronounced influence. This study plays a pivotal role in enhancing recycling efficiency and reducing production costs for waste plastics, especially rPE and rPP-the primary components of plastic waste. By uncovering insights into the degradation effects and material behaviors, our research offers practical pathways for more sustainable waste management. This approach facilitates the optimal utilization of the respective performance characteristics of rPE and rPP, enabling the development of highly cost-effective rPE/rPP blend materials and promoting the efficient reuse of waste materials.

Effect of LNR-g-MMA on the Mechanical Properties and Lifetime Estimation of PLA/PP Blends.

Polylactide (PLA) polymer, polypropylene (PP) polymer, and a PLA/PP (70:30 wt%) blend, with liquid natural rubber-graft-methy methacrylate (LNR-g-MMA) of 0.0, 2.5, 5.0, and 10.0 phr as compatibilizers, were prepared by internal mixing and compression molding. The effect of LNR-g-MMA content on the morphology, mechanical properties, water absorption, thermal degradation, and a lifetime of blends based on PLA and PP was investigated. Scanning electron microscopy (SEM) revealed that the PLA/PP blend underwent phase separation, and the presence of LNR-g-MMA in the PLA/PP blend showed a more homogenized and refined blend morphology. Hence, the addition of LNR-g-MMA was used as a compatibilizer to induce miscibility in the PLA/PP blend. The values of tensile strength, elongation at break, and impact strength of the polymer blends increased, whereas water absorption values decreased with increased LNR-g-MMA content. Thermal degradation kinetics was studied over a temperature range of 50-800 °C with multiple heating rates. The results demonstrated that the thermal stability of blends without LNR-g-MMA was greater than that of blends with LNR-g-MMA and that the thermal stability decreased with increasing LNR-g-MMA content. The activation energy (Ea) was calculated by using the Kissinger-Akahira-Sunose method. The Ea value of PLA was much lower than that of PP, and incorporating PP in the PLA matrix increased the Ea. The addition of LNR-g-MMA to the PLA/PP blend decreased the Ea. The lifetime of PLA/PP blends was reduced with the addition of LNR-g-MMA.

Tough and Thermostable Polybutylene Terephthalate (PBT)/Vitrimer Blend with Enhanced Interfacial Compatibility.

Polymer blending is an efficient way to obtain extraordinary polymeric materials. However, once permanently cross-linked thermosets are involved in blending, there are challenges in designing and optimizing the structures and interfacial compatibility of blends. Vitrimer with dynamic covalent polymer networks provides an innovative opportunity for blending thermoplastics and thermosets. Herein, a reactive blending strategy is proposed to develop thermoplastic-thermoset blend with enhanced compatibility on the basis of dynamic covalent chemistry. Specifically, polybutylene terephthalate (PBT) and polymerized epoxy vitrimer can be directly melt blended to obtain tough and thermostable blends with desirable microstructures and interfacial interaction. Bond exchange facilitates the grafting of PBT and epoxy vitrimer chains, thus enhancing the interfacial compatibility and thermal stability of blends. The obtained blend balances the strength and stretchability of PBT and epoxy vitrimer, resulting in enhanced toughness. This work offers a new way for designing and fabricating new polymeric materials by blending thermoplastics and thermosets. It also suggests a facile direction towards upcycling thermoplastics and thermosets. This article is protected by copyright. All rights reserved.

A sustainable approach to the development of highly degradable packaging films of pectin/guar gum/polyvinyl pyrrolidone: Thermal, biodegradation, and mechanical studies with statistical optimization

AbstractThe use of synthetic packaging materials and mulch films has retrogressive environmental effects. To replace these synthetic materials, high strength biodegradable polymer blends are synthesized using pectin, guar gum and polyvinyl pyrrolidone (PVP). The ternary blends are prepared with guar gum (10%–50%) and PVP (30%–50%), using the solvent casting technique. The experimentation is carried out using a 5 × 3 factorial design and analyzed by response surface methodology. Analysis of variance test is applied to analyze the ultimate tensile strength (UTS) and elongation at break and their simultaneous optimization is done by the desirability index method. The maximum desirability index value (0.877) is achieved at a guar gum content of 50% and PVP content of 41.73%. At this composition, the estimated value of UTS is 24.57 MPa and elongation at break is 27.29%. The thermal stability of the blends is almost similar and they are stable up to 170°C. Initial biodegradation (upto 30 days) of blends increases by 54.82% for samples with higher PVP content and decreases by 43.60% with the increase in guar gum content. All the blends are degraded completely within 90 days. The high tensile properties, sustained thermal stability and complete biodegradation of blends enable these for applications like packaging and agriculture mulch films.

Miscibility and thermal behavior of poly(methyl methacrylate) and polystyrene blend using benzene as a common solvent.

Polymer blending is one of the advanced technologies to attain polymeric material with tailored properties. In this work, the miscibility of Poly(methyl methacrylate) (PMMA) and Polystyrene (PS) blend in benzene was investigated by employing various techniques such as FTIR spectroscopy, viscosity measurement technique, light scattering techniques, DSC and TGA techniques over an extended range of concentrations, compositions, and temperatures. The results revealed that there exist hydrogen bonding and hydrodynamic interactions which led these polymers to get miscible to a large extent. The compatibility increased with the increasing PS contents or increase in temperature of the system. In addition, the thermal stability of blends was found to be improved with the increase in the compatibility of the polymer.

Morphology, thermal properties, mechanical property and degradation of PLGA/PTMC composites

This study demonstrates a dramatic improvement in the mechanical characteristics of PLGA by blending with PTMC. The addition content of 1 wt% PTMC to PLGA matrix had the highest tensile strength and tensile modulus, the values were 57.46 MPa and 1.06 GPa respectively. It is shown that the interfacial compatibility between the component polymers contributes to the formation of super- tough PLGA materials. The result of the FTIR showed that there was no chemical reaction between the two polymers. The thermal stability of blends was slightly reduced, comparing with the PLGA. Crystallization morphology of PLGA/PTMC composites was spherulite. The degradation properties of PLGA/PTMC composites were studied initially after soaking in PBS. The intrinsic viscosity of samples decreased with respect to the soaking time, mass loss decreased more remarkable at 8 weeks, and the tensile strength could maintain 4 weeks. All the results suggested that the PLGA/PTMC composites might develop a novel material to be used as bone repair materials in the future.

Investigation on two modification strategies for the reinforcement of biodegradable lignin/poly(lactic acid) blends

AbstractIn this work, biodegradable lignin/poly(lactic acid) (PLA) blends were prepared with melting compounding method. Dicumyl peroxide (DCP) and maleic anhydride (MA)/biphenyl peroxide (BPO) were used for the modification of the polymer blends, respectively. Structure of the polymer blends was characterized with Fourier transformed infrared spectroscopy and field emission scanning electron microscopy. Mechanical properties of the samples were determined with universal test machine and dynamic mechanical analysis. Thermal behaviors and thermal stability of the blends were all characterized with a thermal gravimetric analysis/differential scanning calorimetry simultaneous thermal analyzer. Lignin reinforced the mechanical strength of the blends while the thermal stability was not improved. At low content, DCP and MA/BPO apparently enhanced the mechanical strength of lignin/PLA blends. However, excessive DCP led to decreased tensile strength and elongation at break. Both DCP and MA/BPO resulted in lower glass transition temperature and melting temperature of PLA in the blends, while the thermal stability of the polymer blends was poorer after modification.

Properties of Poly(Lactic Acid) Blended with Natural Rubber-<i>Graft</i>- Poly(Acrylic Acid)

Poly(acrylic acid) (PAA) was grafted onto natural rubber (NR) to improve the compatibility of NR and poly(lactic acid) (PLA). Polymer blend between PLA and NR-g-PAA was prepared by an internal mixer. Fourier-transform infrared spectroscopy (FT-IR), tensile testing, impact testing, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were employed to determine the functional group, mechanical properties and thermal properties of blends, respectively. Results showed that the addition of NR-g-PAA significantly improved the elongation, impact strength and thermal stability of blends. The P70N30 was the optimum composition to obtain improved mechanical properties of PLA.

Thermal and mechanical properties of polyamide 6/poly(vinyl alcohol) blends with and without peroxides

Polyamide 6 (PA6)/polyvinyl alcohol (PVOH) blends of different compositions (90/10, 80/20, 70/30, 60/40) were prepared using Haake rheomixer. The selected blend compositions (80/20 and 60/40) were modified with peroxides (dicumyl peroxide—DCP and tertiary butyl cumyl peroxide—TBCP). The thermal and mechanical properties of the blends were studied. The thermal stability of blends is found to be intermediate to that of PA6 and PVOH. There is no significant change in thermal stability with the addition of peroxides. The FTIR studies proved good interaction between the components in blend systems. The DSC measurements showed reduction in crystallinity of PA6 with the addition of PVOH. The crystallinity further reduced with the addition of peroxides to the blends, due to the formation of crosslink network. The MFI values decreased with the addition of PVOH and peroxides. The PA6/PVOH blends showed poor mechanical properties, whereas the properties were improved with the addition of peroxides to PA6/PVOH blends.

A novel method for refining of acidic sludge and mixing with vacuum bottom to improve bitumen properties

In this study acidic sludge was refined by a novel method that involves neutralization and extraction of organic compound by a waste solvent. Study on refined sludge indicated that sulfuric acid and major of impurities were removed from sludge. Moreover, resin and asphaltene and accordingly ductility of sludge increased. In continue, different amounts of sludge residue were added to vacuum bottom for bitumen preparation. Test results indicated that sludge residue improved mechanical property and elastic modulus of bitumen. Thermal tests illustrated fine thermal stability of blends at production temperature. Also, aging data described reasonable durability for samples. Consequently, by this approach not only hazardous acidic sludge was eliminated from environment but also it improved mechanical properties of bitumen.

Understanding the effect of silane crosslinking reaction on the properties of PP/POE blends

The effect of silane crosslinking reaction on properties and structure of polypropylene (PP)/ethylene–octene elastomer (POE) blends had been carried out. FTIR and gel content tests confirmed the grafting and crosslinking reaction mechanism of PP/POE blends. The incorporation of POE phase enhanced the crosslinking degree and thermal stability of blends. Crystallinity of silane-crosslinked PP/POE blends decreased sharply, and the melting points change a little with the POE content increasing. The rheological curves of silane-crosslinked PP/POE blends showed an obvious “gel point”, corresponding to the dynamic crosslinking network. Solvent resistance tests suggested crosslinking had a great improvement of solvent resistance. The blends with 30% POE had good comprehensive mechanical properties. Scanning electron microscopy images exhibited that crosslinking had a great influence on the morphologies of silane-crosslinked PP/POE blends. Characterization results indicated the “gel point” acquired from rheology had some corresponding relationship with mechanical properties and solvent resistance.

Enhancing thermal conductivity and near‐infrared radiation reflectance of poly(ε‐caprolactone)/poly(lactic acid)‐based nanocomposites by incorporating hexagonal boron nitride

This work aims to develop multifunctional biodegradable ternary nanocomposites with heat dissipation capability. The effects of adding hexagonal boron nitride (hBN), regarding phase morphology, near‐infrared radiation (NIR) reflectance and thermal conductivity of poly(ε‐caprolactone) (PCL) and poly(lactic acid) (PLA) blends were investigated. The hBN nanoparticles were selectively localized in the PCL phase. Scanning electron microscopy showed that the increased hBN concentration in the PCL/PLA blend led to a more fibrillar PLA phase and, after compression molding, its morphology presented a co‐continuous structure. Adding hBN nanoplatelets increased the reflectance in the NIR region by 184%, the thermal conductivity of the PCL/PLA by 400%, and increased the blend's thermal stability. The co‐continuous morphology could favor the heat flow, because it promotes the confinement of the hBN nanoplatelets in the PCL phase, favoring the conductive thermal pathway formation. POLYM. COMPOS., 40:3464–3471, 2019. © 2019 Society of Plastics Engineers

Influence of blend ratio on the electrical characteristics of vulcanized SBR/NBR blends compatibilized by Cis-polybutadiene rubber

Blends composed of styrene butadiene rubber (SBR) and acrylonitrile-butadiene rubber (NBR) have been fabricated by melt-blending technique using two-roll mill blend machine. Cis-polybutadiene rubber (CBR) was used as a compatibilizer for enhancing the homogeneity between blend phases. No previous reports were found to discuss improving electrical properties of vulcanized SBR/NBR blends using unfilled rubber system (i.e. no fillers incorporation). SEM micrographs were utilized to verify the compatibility between two rubber ingredients in various blends, owing to the use of compatibilizer. Thermal stability of blends was investigated by differential thermal analysis (DTA) and differential scanning calorimetric (DSC) to evaluate the influence of blend ratio on the compatibility of investigated samples. Results revealed that the dielectric properties of blends are dramatically influenced by altering the blend ratio. The results revealed that the SEM observations confirmed the compatibilization effect of CBR on vulcanized SBR/NBR blends. Meanwhile, thermal properties of vulcanized SBR/NBR blends were enhanced with increasing of SBR contents in blends. The complex impedance graphs showed circular arcs showing the bulk contribution to overall electrical behavior for investigated vulcanized SBR/NBR blends. During I-V characteristics have been presented, where a remarkably change from linear behavior to nonlinear conduction at lower temperatures was found for 0SBR/100NBR blends. These findings supported and confirmed that the compatibilization effect and the blend ratio between rubber compositions have strongly influenced on their thermal and electrical properties of vulcanized blends.

Enhancement of Poly(Vinyl Alcohol)–Poly(Vinyl Pyrrolidone) Blend Properties using Modified Copper (II) Oxide and Ultrasonic Irradiation

ABSTRACTCopper (II) oxide nanoparticles supported within poly(vinyl alcohol)/poly(vinyl pyrrolidone) films have been successfully prepared through ultrasonication method. It is discernible that before the preparation of blends, the surface of copper (II) oxide nanoparticles was modified with citric acid and vitamin C as biosafe capping agents. X-ray diffraction scans illustrated the semicrystalline nature of the obtained pure blend and exhibited a good combination between the blend and the modified copper (II) oxide nanoparticles. Also, thermal stability of blends was improved in comparison to the pure polymer blend with increasing modified copper (II) oxide nanoparticles.

Synthesis and characterization of polyethylene/oxidized polyethylene miscible blends and role of OPE as a viscosity control

ABSTRACTPolymer blending allows for new materials to be designed with unique properties. Here, blends of linear low density polyethylene (PE) and oxidized polyethylene (OPE) have been prepared. PE/OPE blends are characterized for their molten state properties by thermal analysis and rheology; the solid state properties are studied by scattering, diffraction, and tensile testing. Melt miscibility was confirmed by a negative Flory‐Huggins interaction parameter (χ ∼ −2.3) from Hoffman‐Weeks plots. Additionally, a continuous decrease in melting temperature (from 123 to 119 °C) and thermal stability of blends (25% weight loss from 454 to 416 °C) was observed with increasing OPE loading from 0 to 50 wt %. Time‐temperature master curves revealed the shifting of the glassy region to higher frequencies and formation of relaxed polymer chains in the glassy region. A plasticization effect was observed with zero shear viscosity of the blends decreasing with increasing OPE loading. Finally, a decrease in lamellar thickness of PE (from 180 to 140 Å) with increasing OPE resulted in increasing the blends' brittleness. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43521.

Thermal, morphology, and mechanical properties of polyphenylene sulfide/polyether sulfone binary blends

ABSTRACTBlends of polyether sulfone (PES) and polyphenylene sulfide (PPS) with different weight ratios (10/0, 8/2, 6/4, 4/6, 2/8, 0/10) were prepared by melt extrusion using a twin‐screw extruder. In this work, the thermal stabilities of blends were evaluated by thermogravimetric analysis and the dynamic mechanical properties were investigated by means of dynamic mechanical analysis. The fracture surfaces were observed with a scanning electron microscopy. In addition, the mechanical property tests were also carried out and the impact strength of blends was improved by 110% compared to that of pure PPS. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41703.

Investigation on the thermal and crystallization behavior of high density polyethylene/acrylonitrile butadiene rubber blends and their composites

The properties of a blend containing a crystallizable component depend largely on the extent of crystallinity and the crystallization behavior of that component in presence of the other. Here, the semi crystalline high density polyethylene (HDPE) is blended with the amorphous elastomer, acrylonitrile butadiene rubber (nitrile rubber or NBR) and we focus mainly on the crystallinity of HDPE/NBR immiscible blends and its variation in the presence of compatibilizer and filler. The effect of blend ratio, compatibilizer concentration, dynamic vulcanization, and filler incorporation were carefully evaluated from the crystallinity measurements using differential scanning calorimeter and the basic aim of this work lies in tuning these conditions. This study allows the elucidation of the influence of crosslink density in regulating the crystallinity of thermoplastic elastomer blends. The scanning electron micrographs provide blend morphology from which the reduced domain size and the influence of NBR particles as heterogeneous nuclei for crystallization are evidenced especially at 5% compatibilizer concentration. The crystallinity of blends was observed to be high at 30 phr carbon black filler addition. Finally, the thermal stability of blends and their composites are also addressed and correlated with the crystallization effect. POLYM. ENG. SCI., 55:1203–1210, 2015. © 2014 Society of Plastics Engineers

Design, synthesis and physical properties of poly(styrene-butadiene-styrene)/poly(thiourea-azo-sulfone) blends

A new aromatic azo-polymer, poly(thiourea-azo-sulfone), has been synthesized using 1-(4-thiocarbamoylaminophenylsulfonylphenyl)thiourea and diazonium salt solution. Conducting and thermally stable rubbery blends of poly(styrene-block-butadiene-block-styrene) (SBS) triblock copolymer and poly(thiourea-azo-sulfone) (PTAS) were produced by solution blending technique. PTAS possessed fine solubility in polar solvents and high molar mass 63 × 103 g moL−1. Microscopic analysis on SBS/PTAS blends revealed good adhesion between the two polymers without macro phase separation. Electrical conductivity measurement recommended that blending of SBS with 60% PTAS was sufficiently conducting 1.43 S cm−1. A relationship between PTAS loading and thermal stability of blends was observed. With the increasing PTAS content, 10% gravimetric loss was increased from 481 to 497 °C, while glass transition improved from 123 to 136 °C (better than neat SBS but lower than PTAS). The blends also established higher tensile strength (52.40–59.96 MPa) relative to SBS. Fine balance of properties renders new SBS/PTAS, potential engineering plastics for a number of aerospace relevance.

Flame retardancy of polystyrene/nylon-6 blends with dispersion of clay at the interface

Abstract Ammonium polyphosphate (APP) and clay were utilized to flame-retard polystyrene/nylon-6 (PS/PA6) blends. The results of FTIR spectra and transmission electron microscopy (TEM) indicated that APP and clay were exclusively dispersed in the PA6 phase. Selective localization of clay at the interface of polymer blends was achieved by the method that poly(styrene-co-maleic anhydride) (SMA) was first reacted with clay, and then blended with PA6/PS. The influences of the distribution of clay and the morphology of PS/PA6 blends on flame retardancy were investigated. The flame retardancy was evaluated by limiting oxygen index (LOI), vertical flammability test, and cone calorimeter tests. For blends with a dispersed PA6 phase, the dispersion of clay in blends has an insignificant effect on the flame retardancy. However, in blends with a continuous PA6 phase, the flame retardancy of blends with clay dispersed at the interface was better than that of blends with clay dispersed in PA6 phase. An investigation of thermo-gravimetric (TG) analysis revealed that the thermal stability of blends with clay dispersed at the interface showed obvious change with blends in which clay dispersed in PA6 phase. Scanning electron microscopy (SEM) characterization showed that the dispersion of clay at the interface had the benefit of forming a compact residue char, which augmented the flame retardancy. A completely loose residue char observed in the blends with continuous PA6 phase in which contained clay platelets should be responsible for the deterioration of flame retardant properties. Energy dispersive spectrometry (EDS) analysis revealed that the reassembling of the clay platelets on the surface of intumescent char caused the formation of loose residue char. On the contrary, the dispersion of clay platelets on whole intumescent char was more favourable to the improvement of flame retardancy.