Article
Polymer Science
Mamoona Tariq, Rabia Khokhar, Arslan Javed, Muhammad Usman, Syed Muhammad Muneeb Anjum, Huma Rasheed, Nadeem Irfan Bukhari, Chao Yan, Hafiz Awais Nawaz
Summary: This study developed reactive anhydride-based oligomers and used them to fabricate gelatin-based crosslinked hydrogels with improved mechanical strengths. These hydrogels varied in their mechanical properties and degradation profiles, but exhibited good cytocompatibility with hADCs. Therefore, oligomer-crosslinked gelatin-based hydrogels hold promise as drug or cell carriers in various biomedical applications.
Article
Chemistry, Physical
Mohammad Nikookar, Mohammad R. Omidkhah, Gholam R. Pazuki, Amir H. Mohammadi
Summary: The study investigated the molecular weight distributions of asphaltene and asphalt, finding that asphaltene has more aggregation at higher molecular weights compared to asphalt, and the molecular weight distribution of asphaltene is generally wider than that of asphalt.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Energy & Fuels
Azadeh Karevan, Shadi Kheirollahi, Mohsen Zirrahi, Hassan Hassanzadeh
Summary: Solvents are injected with steam into oil sands to dilute and mobilize bitumen. However, measuring the solvent content in the produced streams is challenging due to component overlap and the presence of water. In this study, an analytical technique based on GPC and GC was developed to fully characterize complex mixtures of bitumen and solvent and accurately measure the solvent content in the production streams.
Article
Chemistry, Analytical
Sareeha Shamsuddin, Mohammed Awad, Peng Xiang, Solmaz Karamdoust, Eric Landry, Amer Ebied
Summary: This paper presents a novel method for the determination of BA-VA in polymer-based soil palliatives using GPC and H-1 NMR. The results showed that the average dn/dc values for BA-VA copolymer in two dust palliatives were 0.055 and 0.038 mL/g. The extracted BA-VA masses were 1400 and 2900 mg, and the corresponding LOQs using an RI detector were 11.63 and 17.04 μg, respectively.
ANALYTICAL LETTERS
(2023)
Article
Engineering, Chemical
Harshad R. Patil, Sanjay Chauhan, Anurag Mishra, Rudra Prasad Choudhury, Virendrakumar Gupta
Summary: Copolymers of propylene/1-octene and propylene/1-hexene were synthesized in slurry phase polymerization. The effect of Al/Do and Al/Ti mole ratio variations on polymerization and copolymer properties was investigated. The incorporation of comonomer influenced the molecular weight distribution and isotacticity of the resultant copolymers. The copolymer of propylene/1-hexene had a lower melting point compared to the copolymer of propylene/1-octene. The copolymers had a broad molecular weight distribution compared to homo PP. C-13 NMR was used to quantitatively evaluate the incorporation of comonomer. Copolymerization of propylene with hexene resulted in a copolymer with a relatively higher amount of 1-hexene compared to the copolymer of propylene/1-octene with a similar catalyst system, which explains the lower peak melting points.
POLYMER ENGINEERING AND SCIENCE
(2022)
Article
Polymer Science
Harshad R. Patil, Sangeetha Karthikeyan, Vikas Kote, Pratyay Sengupta, Pratyagra Samanta, Pooja Kadam, Natarajan Venkateswaran, Virendra Kumar Gupta
Summary: In this study, the molecular weight distribution curves of different polyolefins were deconvoluted to reveal the distribution and characteristics of active sites in different catalysts. The results showed that the JDE method provided a highly accurate fit for the molecular weight distribution of the polymers. This research is of great importance for understanding the role of catalyst active sites and their impact on polymer properties.
Article
Construction & Building Technology
M. Refaie, Alaa Mohsen, El-Sayed A. R. Nasr, Mohamed Kohail
Summary: The study aims to develop a synthetic polymer with superior plasticizing properties in a highly alkaline medium. A laboratory-prepared superplasticizer called phenol-formaldehyde sulfonilate (PFS) was synthesized and compared with two commercial superplasticizers. The results showed that PFS exhibited good stability and dispersing efficiency, and enhanced the physicomechanical properties of alkali-activated slag mixes.
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
(2023)
Article
Engineering, Chemical
Farzad Jani, Abdolhannan Sepahi, Seyyed Kamal Afzali, Saeed Houshmand Moayed
Summary: This article evaluates the effect of microstructure on the mechanical properties of high-density polyethylene (HDPE), specifically the molecular weight distribution and chemical composition distribution. The study finds that highly branched low molecular weight chains result in longer crystallization time, while an increased ratio of CEF eluted fraction below 80 degrees C to the crystallizable fraction leads to decreased entanglement density and impact strength, and increased average lamella thickness.
POLYMER ENGINEERING AND SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Rene Burger, Jessica Rumpf, Xuan Tung Do, Yulia B. Monakhova, Bernd W. K. Diehl, Matthias Rehahn, Margit Schulze
Summary: This study demonstrates that the use of H-1 NMR and DOSY NMR data combined with multivariate regression methods can successfully determine the molecular weight and polydispersity of lignins. The prediction errors for the validation samples were consistent with the results from the models, indicating the potential of NMR measurements combined with multivariate regression methods as an alternative to more time-consuming methods like gel permeation chromatography.
Article
Polymer Science
Mei Hong, Wei Liu, Yonggang Liu, Xuemin Dai, Yu Kang, Rui Li, Feng Bao, Xuepeng Qiu, Yanxiong Pan, Xiangling Ji
Summary: Polyamic acid (PAA) is the precursor of polyimide (PI) and its molecular weight plays a significant role in the preparation and performance of PI. However, accurately characterizing the molecular weight of PAA is challenging due to the complex interactions in the solution system. This study utilized gel permeation chromatography coupled with differential refractive index and multi-angle laser light scattering detectors to measure the molecular weight of (6FDA-DMB) PAA. The combination of LiBr and HAc was found to effectively suppress the complex interactions and facilitate the separation of PAA. The optimized mobile phase, 0.02 M LiBr/0.2 M HAc/DMF, yielded reproducible results for the molecular weight of PAA.
Article
Food Science & Technology
Anna Arina Bt Ab. Halim, Mohd Y. Rafii, Mohamad B. Osman, Samuel C. Chukwu, Yusuff Oladosu
Summary: Heat treatment affects the structure and properties of rice varieties. This study examined the effects of heat treatment on the physicochemical properties and tissue structure of Mahsuri Mutan, Basmati 370, and MR219 rice varieties. The results showed that heat treatment significantly influenced the physicochemical traits and starch structure of the rice samples.
Article
Chemistry, Analytical
Evamaria C. Gaugler, Wolfgang Radke, Andrew P. Vogt, Dawn A. Smith
Summary: Molar masses, MHS exponents, and dn/dc values of three lignins were determined in DMF with 0.05 M LiBr using multi-detector GPC. The ineffectiveness of fluorescence filters on molar mass determination by GPC-MALS was confirmed, and GPC with viscometry detection showed compact molecular structures for the lignins. Intrinsic viscosity of Protobind 1000 was lower than that of Alcell or Indulin AT for a given molar mass.
JOURNAL OF ANALYTICAL SCIENCE AND TECHNOLOGY
(2021)
Article
Polymer Science
Julia Cuthbert, Shiwanka Wanasinghe, Krzysztof Matyjaszewski, Dominik Konkolewicz
Summary: Polymer networks synthesized by ATRP and RAFT showed differences in properties at both molecular and bulk levels, with ATRP potentially providing better control at longer chain lengths. Both methods resulted in similar properties at shorter chain lengths, indicating control through soluble components like catalyst in ATRP and soluble polymer fractions in RAFT.
Article
Chemistry, Multidisciplinary
Wuchao Zhao, Fukuan Li, Chengkai Li, Jianghua He, Yuetao Zhang, Changle Chen
Summary: This study applied Lewis pairs composed of N-heterocyclic olefins and Al-based compounds for 1,4-selective polymerization of (E,E)-methyl sorbate and (E,E)-ethyl sorbate. The system exhibited high catalytic activity and initiation efficiency with the formation of polymers with tunable molecular weight and narrow molecular weight distribution. Additionally, block copolymerization and conversion to different polymers with strict sequence structures were realized.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Shagufta Jabin, Jitander Kumar Kapoor, Sapana Jadoun, Nisha Chandna, Narendra Pal Singh Chauhan
Summary: Successful treatment of sugar industrial effluent using polyelectrolytes and inorganic coagulants was achieved. Four new polyamine-based cationic polyelectrolytes were synthesized and characterized. Among them, polyelectrolytes with a 1.5:1 molar ratio of epichlorohydrin: diphenylamine showed the best efficiency in pollutant removal from sugar industry wastewater. This result was consistent across all types of sugar industry suspensions.
JOURNAL OF MOLECULAR STRUCTURE
(2023)
Article
Polymer Science
Sanjay Chauhan, Sanket Shah, Harshad R. Patil, Virendrakumar Gupta
Summary: The study successfully synthesized MGA in lab and demo pilot scale, evaluated their effects on ZN catalyst and PP resin characteristics. The results suggest that optimized concentration of methanol is critical for achieving improved ZN catalyst and PP resin properties.
JOURNAL OF POLYMER RESEARCH
(2021)
Article
Polymer Science
Jessy Joseph, T. K. Sreethu, Subhra Mohanty, Virendra Kumar Gupta, Anil K. Bhowmick
Summary: Metal-organic framework (MOF) was utilized as a reinforcing filler for rubber for the first time, showing improved mechanical properties and thermal stability compared to traditional fillers such as nano alumina. The porous organic structure of MOF promoted enhanced entanglement of polymer chains at the interface, leading to superior dispersion and compatibility in the rubber matrix. This study suggests that MOF could be a promising nanofiller for applications in the rubber industry.
RUBBER CHEMISTRY AND TECHNOLOGY
(2021)
Review
Polymer Science
Parashiva C. Prabhu, Subhra Mohanty, Virendra Kumar Gupta
Summary: This review explores developments in the modification of polybutadiene rubber (PBR) through processes such as hydrogenation and functionalization, highlighting the importance of reaction conditions and suitable catalysts. It discusses reactivity ratios associated with microstructures and possible mechanisms, emphasizing the impact of reaction conditions on product properties. Industrial applications of modified PBR and their availability in the global market are also addressed.
RUBBER CHEMISTRY AND TECHNOLOGY
(2021)
Article
Polymer Science
Amit Kumar, Subhra Mohanty, Virendra Kumar Gupta
Summary: This review focuses on the synthesis of BR using various transition metal catalysts and introduces the application of new generation metal complexes as catalysts in BR production. The role of catalysts in producing BR with different microstructures and the effect of transition metal catalysts on activity and stereoselectivity of polymers are discussed in detail.
RUBBER CHEMISTRY AND TECHNOLOGY
(2021)
Article
Polymer Science
Harshad R. Patil, Sangeetha Karthikeyan, Vikas Kote, Pratyay Sengupta, Pratyagra Samanta, Pooja Kadam, Natarajan Venkateswaran, Virendra Kumar Gupta
Summary: In this study, the molecular weight distribution curves of different polyolefins were deconvoluted to reveal the distribution and characteristics of active sites in different catalysts. The results showed that the JDE method provided a highly accurate fit for the molecular weight distribution of the polymers. This research is of great importance for understanding the role of catalyst active sites and their impact on polymer properties.
Article
Polymer Science
Hiren Bhajiwala, H. R. Imam Khasim, Rajendra B. Patankar, Bhavesh Desai, Virendra K. Gupta
Summary: In this study, core-sheath fibers of polyvinyl alcohol/polyethylene composites were successfully synthesized using titanium tetrachloride incorporated PVA nanofiber as catalyst precursor and methyl aluminoxane as a cocatalyst. The thermal analysis confirmed the presence of polyethylene in the composite fibers.
EUROPEAN POLYMER JOURNAL
(2022)
Article
Engineering, Chemical
Harshad R. Patil, Sanjay Chauhan, Anurag Mishra, Rudra Prasad Choudhury, Virendrakumar Gupta
Summary: Copolymers of propylene/1-octene and propylene/1-hexene were synthesized in slurry phase polymerization. The effect of Al/Do and Al/Ti mole ratio variations on polymerization and copolymer properties was investigated. The incorporation of comonomer influenced the molecular weight distribution and isotacticity of the resultant copolymers. The copolymer of propylene/1-hexene had a lower melting point compared to the copolymer of propylene/1-octene. The copolymers had a broad molecular weight distribution compared to homo PP. C-13 NMR was used to quantitatively evaluate the incorporation of comonomer. Copolymerization of propylene with hexene resulted in a copolymer with a relatively higher amount of 1-hexene compared to the copolymer of propylene/1-octene with a similar catalyst system, which explains the lower peak melting points.
POLYMER ENGINEERING AND SCIENCE
(2022)
Review
Engineering, Chemical
Prasanta Kumar Behera, Amit Kumar, Subhra Mohanty, Virendra Kumar Gupta
Summary: Butyl and halobutyl rubber are important polymeric materials with potential applications in various areas. Functionalization of these rubbers through postpolymerization modification plays a crucial role in tailoring their properties. This review discusses the development of functionalized rubbers and their improved properties and new applications.
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
(2022)
Article
Polymer Science
Parthiv M. Trivedi, Chandra Prakash Gocher, Vijai Balachandran, Virendra Kumar Gupta
Summary: This study reports the synthesis of polypropylene products using a MgCl2 supported multidentate Ziegler-Natta (Z-N) pre-catalyst. Compared to conventional bidentate Z-N pre-catalysts, the multidentate Z-N pre-catalyst showed better hydrogen response and controlled isotacticity in propylene polymerization. Melt rheology analysis showed higher modulus values for ultra-high molecular weight isotactic polypropylene (UHMWiPP) compared to medium molecular weight PP resins. GPC analysis revealed a medium to broad unimodal molecular weight distribution (MWD) for PP products produced with the multidentate Z-N pre-catalyst system.
JOURNAL OF APPLIED POLYMER SCIENCE
(2023)
Article
Chemistry, Physical
K. Vipin Raj, Virendra Kumar Gupta, Kumar Vanka
Summary: Ziegler-Natta (Z-N) systems are efficient heterogeneous catalysts for the production of isotactic polypropylene and polyethylene. External donors significantly improve the stereoselectivity of polymerization by coordinating at vacant sites created by the extraction of internal donors. DFT studies show that the bite difference problem between internal and external donors can be overcome by the formation of adducts between external alkoxysilane donors and AlEt2Cl in the Z-N systems, which enhances the stereoselectivity of the catalysts.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Mechanics
Vincenzo Ianniello, Salvatore Costanzo, Rossana Pasquino, Giovanni Ianniruberto, Virendra K. Gupta, Lucas Stieglitz, Bernhard Rieger, Theo Tervoort, Nino Grizzuti
Summary: This study examines the possibility of determining the molecular weight distribution (MWD) of linear ultrahigh molecular weight (UHMW) polypropylene (PP) using rheology. Various UHMWPP samples are analyzed using linear viscoelastic measurements and creep experiments to calculate the terminal relaxation. The results are compared with gel permeation chromatography (GPC) data using a mixing rule based on the relaxation modulus. Material parameters governing the stress relaxation of PP are estimated from lab-made UHMWPP samples, and this information is used to predict the MWD of other samples. The direct and inverse problems of obtaining rheological responses from MWD and vice versa are solved, showing satisfactory agreement between calculated and measured MWD.
Article
Engineering, Chemical
Ritesh J. Dhanorkar, Subhra Mohanty, Ashok Misra, Virendra Kumar Gupta
Summary: Nanoemulsion polymerization is a new process for synthesizing specialty-purpose latexes. Styrene and 1,4-butadiene polymerization were demonstrated using a nanoemulsion-based method. Conventional emulsifiers were used to prepare base emulsions with small particle sizes. The use of nanoemulsion improved the efficiency and quality of emulsion, leading to higher productivity. These latexes have high molecular weight polymers with small particle sizes, making them ideal for coating applications. A comparison was made between nanoemulsion-based polymer and conventional macroemulsion-based product.
POLYMER ENGINEERING AND SCIENCE
(2023)
Review
Polymer Science
Sangeetha Karthikeyan, Virendra Kumar Gupta
Summary: Highly reactive polyisobutylene (HRPIB) is a crucial industrial polymer used extensively as additives for lubricants, fuels and polymers. This review focuses on the synthetic processes of HRPIB, particularly the carbocationic approach, organometallic catalyst systems and carbocationic polymerization with Lewis acid-based chain transfer promoting catalysts. The use of Lewis acid complexes with ionic liquids has shown great potential in producing HRPIB with desired characteristics. Future advancements need to consider economic and environmentally-friendly approaches to ensure valuable commercial processes and HRPIB products.
JOURNAL OF POLYMER RESEARCH
(2023)
Review
Polymer Science
Denial Mahata, Sangeetha Karthikeyan, Rahul Godse, Virendra Kumar Gupta
Summary: Poly(butylene adipate-co-terephthalate) is a unique biodegradable copolyester with a complex synthesis process requiring high temperatures and vacuum conditions. Research focuses on developing methods for commercial scale synthesis and investigating different grades of the product with additives and nanocomposites.
POLYMER SCIENCE SERIES C
(2021)
Review
Chemistry, Multidisciplinary
Anurag Mishra, Harshad R. Patil, Virendrakumar Gupta
Summary: In recent years, transition metal catalysts for propylene polymerization and copolymerization have shown significant progress, with a shift towards new generation catalysts including non-metallocene catalysts and late transition-metal catalysts. The focus is on the reactivity, selectivity, and resulting properties of the polymers, with an emphasis on the design of catalysts for different comonomers.
NEW JOURNAL OF CHEMISTRY
(2021)
