S Aparna - Academia.edu (original) (raw)

Papers by S Aparna

Research paper thumbnail of Review on nano‐and microfiller‐based polyamide 6 hybrid composite: Effect on mechanical properties and morphology

Polymer Engineering & Science, 2020

Polyamide 6 (PA6)‐based composites are of evolving interest due to its high strength, wear resist... more Polyamide 6 (PA6)‐based composites are of evolving interest due to its high strength, wear resistance, and barrier properties. The use of binary composites mostly with nanomaterial and glass fibers has been reviewed and presented in literature. However to obtain a balance of properties like stiffness, toughness, and strength along with cost reduction, ternary composites of PA6 have been designed. To achieve the balance, PA6 blend‐based composites, with combination of microfiller/nanofiller or PA6 with combination micro‐microfiller, PA6 with microfiller/nanofiller and fiber have been designed. The properties of PA6‐based ternary hybrid composites depend on type of dispersed phase used, presence of compatibilizer, type of filler used (nanofiller or microfiller or fiber or hybrid) and combination of fillers used. However, a review in this direction is not available in literature. Here, in this study, an overall understanding of various fillers, dispersed phase, and their combinations c...

Research paper thumbnail of Influence of PP content on mechanical properties, water absorption, and morphology in PA6/PP blend

Journal of Applied Polymer Science, 2019

ABSTRACTPA6/polypropylene (PP) blends are investigated for obtaining balanced strength and toughn... more ABSTRACTPA6/polypropylene (PP) blends are investigated for obtaining balanced strength and toughness. The focus of this study is to understand the effect of PP content on mechanical property, water absorption, impact strength, thermal behavior, and morphology of PP in the absence and presence of PP‐g‐maleic anhydride compatibilizer. In comparison to pure PA6, all blends have higher impact strength with 161 and 124% increase at 5 wt % PP content in uncompatibilized and compatibilized blends (UB and CB), respectively. Morphology of impact fractured samples shows brittle fracture in the case of CB. scanning electron microscope of cryogenically fractured samples show decrease in domain size and change in shape from ellipsoid to spherical, from UB to CB. Then, 75% reduction in water absorption is observed for 50 wt % PP content UB. Postwater absorption yield strength (YS) remains constant above 10 wt % PP in both UB and CB and decrease in YS is less at higher PP content in CB. © 2019 Wil...

Research paper thumbnail of Comparative study between dry and wet properties of thermoplastic PA6/PP novel matrix-based carbon fibre composites

Science and Engineering of Composite Materials, 2021

The aim of the study is to develop and investigate the suitability of thermoplastic composites fo... more The aim of the study is to develop and investigate the suitability of thermoplastic composites for underwater applications. PA6/PP/PP-g-MA (70 wt%/30 wt%/3 phr) blend is used as a novel matrix to synthesize UDCF composites with balanced strength and toughness even in humid conditions. This novel matrix has around 60% lower water absorption capacity compared to PA6. Short carbon fibres (SCF) and unidirectional carbon fibre fabric (UDCF with 12K rovings) are used as reinforcements. X-ray CT data of injection-molded SCF composites revealed good wetting. However, in the case of compression-molded UDCF composites, a few unwetted zones were found. Comparing dry and wet samples, wet-matrix, wet-SCF composite and wet-UDCF composites had 40, 15, and 25% reduction in their tensile strengths, respectively. However, the impact strength of wet-matrix and wet-UDCF composites increased by 67 and 61%, respectively. Hence, SCF composites having a wet tensile strength of 46 MPa can be used in prepari...

Research paper thumbnail of Studies on Biocide Encapsulated Zeolite-epoxy Nano Hybrid Coatings on Mild Steel

Current Bionanotechnology, 2015

The present study aims at the fabrication of nano-hybrid coatings using diglycidyl ethers of bisp... more The present study aims at the fabrication of nano-hybrid coatings using diglycidyl ethers of bisphenol-A (DGEBA) as matrix material modified with effective low cost as well as less toxic antifoulants viz., benzoic acid (BA) and sodium benzoate (SB), which are encapsulated into nanozeolite containers as reinforcing materials that could be utilized for marine coatings. These two antifoulants were incorporated into epoxy antifouling (AF) coatings separately in the amount of (1, 3, 5, 7 and 10 wt. %) to investigate their corrosion resistant behaviour and antifouling capabilities. Corrosion rate of 3 wt. % SB incorporated epoxy AF coating was determined to be much lower than that of 3 wt. % BA incorporated epoxy AF coating. A direct relationship between the corrosion rate, antifouling nature, antibacterial behaviour and toxicity was observed by electrochemical impedance spectroscopy, salt spray test, static immersion study, antibacterial test and acute toxicity tests. The SB encapsulated coating with 3 wt. % loading exhibits enhanced antifouling and corrosion resistance performance, while AF coatings contains 5 wt. % loading of BA showed a marked reduction in fouling attachment than other coating compositions.

Research paper thumbnail of Natural Biocide Loaded PLA Films for a Possible Packaging Application

Journal of Advanced Microscopy Research, 2018

Research paper thumbnail of Review on Various Compatibilizers and its Effect on Mechanical Properties of Compatibilized Nylon Blends

Polymer-Plastics Technology and Engineering, 2016

Nylon 6 blends such as PA6/ABS, PA6/PP etc. are among the commercially successful blends, having ... more Nylon 6 blends such as PA6/ABS, PA6/PP etc. are among the commercially successful blends, having varied applications ranging from automobile parts to construction industry. Nylon 6 blends can be made super tough based on the other polymer involved. Nylon 6 blends are immiscible, and use of compatibilizers can increase the interfacial adhesion between the polymers. Amount of compatibilizer plays a key role in defining the size distribution, dispersion and adhesion between the polymers. In this paper a detailed review on the compatibilizers used and the effect of compatibilizer on the mechanical and impact properties of the blends has been given.

Research paper thumbnail of Effect of short carbon fiber content and water absorption on tensile and impact properties of PA6/PP blend based composites

Polymer Composites, 2020

PA6 absorbs moisture, restricting its use in humid applications. The first objective of this stud... more PA6 absorbs moisture, restricting its use in humid applications. The first objective of this study is to process composite parts to be used in high humid applications using PA6 blend based matrix (PA6/PP/PP-g-MA) and SCF (3-15 wt%) reinforcement. The second objective is to perform tensile and impact tests in both dry and wet conditions. The third objective is to carry out the in-depth analysis of fractography of blends and composites. For blend, more than 50% reduction in water absorption was observed in comparison to pure PA6, indicating the need to blend with PP. The tensile strength of the composite with 15 wt% SCF was 55% and 133% higher than matrix blend in dry and wet conditions respectively indicating the need to reinforce the blend with SCF. Injection molded composites with 15 wt% SCF revealed the tensile strength of 54 MPa, 46 MPa and modulus of 5 GPa, 4 GPa in dry, wet state respectively. At higher SCF content, both SCF and PP are well dispersed in PA6 matrix but fiber pull out led to fracture of dry samples. Post water absorption, tensile fractured samples showed significant fiber pull out, indicating reduction in interfacial adhesion due to water absorption.

Research paper thumbnail of Skeletally Modified Polyamide Flame Retardant Coatings

OALib, 2014

The use of polyamide coatings for electrical applications is restricted mainly because of its ina... more The use of polyamide coatings for electrical applications is restricted mainly because of its inadequate flame retardant behaviour. In order to improve its flame retardant behaviour, polyamide is modified by incorporating phosphorus moiety in its backbone. The structure of the phosphorus and poly amide was confirmed by infrared spectroscopy (FT-IR), NMR, thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), UL-94 vertical burning tests and char residue tests. From the results obtained, we observe that the incorporation of phosphorus into the polyamide enhances its thermal stability and flame retardancy.

Research paper thumbnail of Surface Modified Carbon Fibre Reinforced PA6 and its Blend-Based Composites

Lecture Notes in Mechanical Engineering, 2019

Polyamide 6 (PA6) matrix-based composite system are widely used in automotive sector. PA6 can be ... more Polyamide 6 (PA6) matrix-based composite system are widely used in automotive sector. PA6 can be directly used as matrix material, but for avoiding the moisture intake by PA6, Polypropylene (PP) has been used as a secondary polymer and PP grafted with maleic anhydride (PP-g-MA) has been used as compatibilizer. The use of carbon fibre as reinforcement increases the strength and stiffness of the composite. Laminate composites have been studied for automotive and wind turbine blade application. But, commercially injection moulding is used for making automobile components. In that case, short carbon fibre (SCF) can be used as reinforcement. In this study, the effect of surface treatment of SCF on mechanical properties of PA6 and its blend-based composites has been studied. Two types of modification have been compared viz., sizing and coupling agent. To investigate the effect of sizing and coupling agent, commercially available SCF was desized by thermal etching and then modified with suitable amount of epoxy and silane as sizing and coupling agent, respectively, and its effect on PA6 and modified PA6 matrix was studied. Mechanical properties and thermal properties of the composites were studied using tensile testing and DSC analysis. It was found that epoxy-based sizing is suitable for PA6 and silane-based coupling agent is suitable for blend-based PA6 matrix.

Research paper thumbnail of Review on nano‐and microfiller‐based polyamide 6 hybrid composite: Effect on mechanical properties and morphology

Polymer Engineering & Science, 2020

Polyamide 6 (PA6)‐based composites are of evolving interest due to its high strength, wear resist... more Polyamide 6 (PA6)‐based composites are of evolving interest due to its high strength, wear resistance, and barrier properties. The use of binary composites mostly with nanomaterial and glass fibers has been reviewed and presented in literature. However to obtain a balance of properties like stiffness, toughness, and strength along with cost reduction, ternary composites of PA6 have been designed. To achieve the balance, PA6 blend‐based composites, with combination of microfiller/nanofiller or PA6 with combination micro‐microfiller, PA6 with microfiller/nanofiller and fiber have been designed. The properties of PA6‐based ternary hybrid composites depend on type of dispersed phase used, presence of compatibilizer, type of filler used (nanofiller or microfiller or fiber or hybrid) and combination of fillers used. However, a review in this direction is not available in literature. Here, in this study, an overall understanding of various fillers, dispersed phase, and their combinations c...

Research paper thumbnail of Influence of PP content on mechanical properties, water absorption, and morphology in PA6/PP blend

Journal of Applied Polymer Science, 2019

ABSTRACTPA6/polypropylene (PP) blends are investigated for obtaining balanced strength and toughn... more ABSTRACTPA6/polypropylene (PP) blends are investigated for obtaining balanced strength and toughness. The focus of this study is to understand the effect of PP content on mechanical property, water absorption, impact strength, thermal behavior, and morphology of PP in the absence and presence of PP‐g‐maleic anhydride compatibilizer. In comparison to pure PA6, all blends have higher impact strength with 161 and 124% increase at 5 wt % PP content in uncompatibilized and compatibilized blends (UB and CB), respectively. Morphology of impact fractured samples shows brittle fracture in the case of CB. scanning electron microscope of cryogenically fractured samples show decrease in domain size and change in shape from ellipsoid to spherical, from UB to CB. Then, 75% reduction in water absorption is observed for 50 wt % PP content UB. Postwater absorption yield strength (YS) remains constant above 10 wt % PP in both UB and CB and decrease in YS is less at higher PP content in CB. © 2019 Wil...

Research paper thumbnail of Comparative study between dry and wet properties of thermoplastic PA6/PP novel matrix-based carbon fibre composites

Science and Engineering of Composite Materials, 2021

The aim of the study is to develop and investigate the suitability of thermoplastic composites fo... more The aim of the study is to develop and investigate the suitability of thermoplastic composites for underwater applications. PA6/PP/PP-g-MA (70 wt%/30 wt%/3 phr) blend is used as a novel matrix to synthesize UDCF composites with balanced strength and toughness even in humid conditions. This novel matrix has around 60% lower water absorption capacity compared to PA6. Short carbon fibres (SCF) and unidirectional carbon fibre fabric (UDCF with 12K rovings) are used as reinforcements. X-ray CT data of injection-molded SCF composites revealed good wetting. However, in the case of compression-molded UDCF composites, a few unwetted zones were found. Comparing dry and wet samples, wet-matrix, wet-SCF composite and wet-UDCF composites had 40, 15, and 25% reduction in their tensile strengths, respectively. However, the impact strength of wet-matrix and wet-UDCF composites increased by 67 and 61%, respectively. Hence, SCF composites having a wet tensile strength of 46 MPa can be used in prepari...

Research paper thumbnail of Studies on Biocide Encapsulated Zeolite-epoxy Nano Hybrid Coatings on Mild Steel

Current Bionanotechnology, 2015

The present study aims at the fabrication of nano-hybrid coatings using diglycidyl ethers of bisp... more The present study aims at the fabrication of nano-hybrid coatings using diglycidyl ethers of bisphenol-A (DGEBA) as matrix material modified with effective low cost as well as less toxic antifoulants viz., benzoic acid (BA) and sodium benzoate (SB), which are encapsulated into nanozeolite containers as reinforcing materials that could be utilized for marine coatings. These two antifoulants were incorporated into epoxy antifouling (AF) coatings separately in the amount of (1, 3, 5, 7 and 10 wt. %) to investigate their corrosion resistant behaviour and antifouling capabilities. Corrosion rate of 3 wt. % SB incorporated epoxy AF coating was determined to be much lower than that of 3 wt. % BA incorporated epoxy AF coating. A direct relationship between the corrosion rate, antifouling nature, antibacterial behaviour and toxicity was observed by electrochemical impedance spectroscopy, salt spray test, static immersion study, antibacterial test and acute toxicity tests. The SB encapsulated coating with 3 wt. % loading exhibits enhanced antifouling and corrosion resistance performance, while AF coatings contains 5 wt. % loading of BA showed a marked reduction in fouling attachment than other coating compositions.

Research paper thumbnail of Natural Biocide Loaded PLA Films for a Possible Packaging Application

Journal of Advanced Microscopy Research, 2018

Research paper thumbnail of Review on Various Compatibilizers and its Effect on Mechanical Properties of Compatibilized Nylon Blends

Polymer-Plastics Technology and Engineering, 2016

Nylon 6 blends such as PA6/ABS, PA6/PP etc. are among the commercially successful blends, having ... more Nylon 6 blends such as PA6/ABS, PA6/PP etc. are among the commercially successful blends, having varied applications ranging from automobile parts to construction industry. Nylon 6 blends can be made super tough based on the other polymer involved. Nylon 6 blends are immiscible, and use of compatibilizers can increase the interfacial adhesion between the polymers. Amount of compatibilizer plays a key role in defining the size distribution, dispersion and adhesion between the polymers. In this paper a detailed review on the compatibilizers used and the effect of compatibilizer on the mechanical and impact properties of the blends has been given.

Research paper thumbnail of Effect of short carbon fiber content and water absorption on tensile and impact properties of PA6/PP blend based composites

Polymer Composites, 2020

PA6 absorbs moisture, restricting its use in humid applications. The first objective of this stud... more PA6 absorbs moisture, restricting its use in humid applications. The first objective of this study is to process composite parts to be used in high humid applications using PA6 blend based matrix (PA6/PP/PP-g-MA) and SCF (3-15 wt%) reinforcement. The second objective is to perform tensile and impact tests in both dry and wet conditions. The third objective is to carry out the in-depth analysis of fractography of blends and composites. For blend, more than 50% reduction in water absorption was observed in comparison to pure PA6, indicating the need to blend with PP. The tensile strength of the composite with 15 wt% SCF was 55% and 133% higher than matrix blend in dry and wet conditions respectively indicating the need to reinforce the blend with SCF. Injection molded composites with 15 wt% SCF revealed the tensile strength of 54 MPa, 46 MPa and modulus of 5 GPa, 4 GPa in dry, wet state respectively. At higher SCF content, both SCF and PP are well dispersed in PA6 matrix but fiber pull out led to fracture of dry samples. Post water absorption, tensile fractured samples showed significant fiber pull out, indicating reduction in interfacial adhesion due to water absorption.

Research paper thumbnail of Skeletally Modified Polyamide Flame Retardant Coatings

OALib, 2014

The use of polyamide coatings for electrical applications is restricted mainly because of its ina... more The use of polyamide coatings for electrical applications is restricted mainly because of its inadequate flame retardant behaviour. In order to improve its flame retardant behaviour, polyamide is modified by incorporating phosphorus moiety in its backbone. The structure of the phosphorus and poly amide was confirmed by infrared spectroscopy (FT-IR), NMR, thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), UL-94 vertical burning tests and char residue tests. From the results obtained, we observe that the incorporation of phosphorus into the polyamide enhances its thermal stability and flame retardancy.

Research paper thumbnail of Surface Modified Carbon Fibre Reinforced PA6 and its Blend-Based Composites

Lecture Notes in Mechanical Engineering, 2019

Polyamide 6 (PA6) matrix-based composite system are widely used in automotive sector. PA6 can be ... more Polyamide 6 (PA6) matrix-based composite system are widely used in automotive sector. PA6 can be directly used as matrix material, but for avoiding the moisture intake by PA6, Polypropylene (PP) has been used as a secondary polymer and PP grafted with maleic anhydride (PP-g-MA) has been used as compatibilizer. The use of carbon fibre as reinforcement increases the strength and stiffness of the composite. Laminate composites have been studied for automotive and wind turbine blade application. But, commercially injection moulding is used for making automobile components. In that case, short carbon fibre (SCF) can be used as reinforcement. In this study, the effect of surface treatment of SCF on mechanical properties of PA6 and its blend-based composites has been studied. Two types of modification have been compared viz., sizing and coupling agent. To investigate the effect of sizing and coupling agent, commercially available SCF was desized by thermal etching and then modified with suitable amount of epoxy and silane as sizing and coupling agent, respectively, and its effect on PA6 and modified PA6 matrix was studied. Mechanical properties and thermal properties of the composites were studied using tensile testing and DSC analysis. It was found that epoxy-based sizing is suitable for PA6 and silane-based coupling agent is suitable for blend-based PA6 matrix.