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The demand for biobased materials for various end-uses in the bioplastic industry is substantially growing due to increasing awareness of health and environmental concerns, along with the toxicity of synthetic plasticizers such as phthalates. This fact has stimulated new regulations requiring the replacement of synthetic conventional plasticizers, particularly for packaging applications. Biobased plasticizers have recently been considered as essential additives, which may be used during the processing of compostable polymers to enormously boost biobased packaging applications. The development and utilization of biobased plasticizers derived from epoxidized soybean oil, castor oil, cardanol, citrate, and isosorbide have been broadly investigated. The synthesis of biobased plasticizers derived from renewable feedstocks and their impact on packaging material performance have been emphasized. Moreover, the effect of biobased plasticizer concentration, interaction, and compatibility on the polymer properties has been examined. Recent developments have resulted in the replacement of synthetic plasticizers by biobased counterparts. Particularly, this has been the case for some biodegradable thermoplastics-based packaging applications.

Extensively used petrochemical polymers possess harmful influence on the ecosystem, therefore the utilizing of bio-based materials should be essentially important to employ in wide range of applications, due to positive affect to the environment. The advantage of these materials significantly enhances the carbon footprint and has a helpful impact on the life cycle assessment (LCA) of plastic products; consequently, the development of biobased thermoplastic polyurethane (bio-TPU) from renewable resources is gain much interested from various polymers industries. In addition, recent advances in biotechnology dedicate toward produce a new class of TPU to be developed from plant-based biomass. Thus, this review focuses on recent advances of bio-TPU formulations. Factors effecting the TPU formulation are presented in view of the potential applications in various fields. Biodegradation of TPU and some aspects accelerating their biodegradability are also described.

The development of biobased polyurethane foam (PUF) from renewable resources of polyol against traditional PUF has attracted many researchers and investors. The reduction or elimination of petrochemical material has had an increased contribution to producing more sustainable PUF. This chapter aims to present an overview of the work accomplished to synthesize green chemistries from plant-based biomass by using the green polyol to produce a renewable foam. The effect of different bio-polyol grades, catalysts, chain extenders, surfactants, and blowing agents were discussed. However, despite their advantages, degradable polyesters have lack of optimum properties and fail to meet the desired mechanical and physical properties. Therefore, bio-additives require to modify and compensate in mechanical properties with increase environmentally friendly foam. Moreover, reinforced bio-additives have several key advantages over other synthesis methods, such as reduced fossil-based feedstock reliance, decreased CO2 emissions, renewable foam, and high productivity. Recent advances in chemistry and technology of sustainable routes for the synthesis of NIPUs were also described.

Retraction Note: The Editor-in-Chief has retracted this article [1] following an investigation by Ryerson University. Concerns were raised regarding Figure 13C. It appears that parts of Figure 13C overlap with Figure 13B. As a result of the University’s inquiry into this matter, it was determined that the research in question underlying the publication was not undertaken within Ryerson labs and a copy of the data was not retained by the authors. As the authors were not able to produce a copy of the underlying data for independent verification, they have agreed to retract the article. Mustafa Abu Ghalia, Ibrahim Inuwa, Azman Hassan, and Yaser Dahman agree to this retraction.

Natural fillers including cellulose, chitin, hazelnut, and eggshell are some of the most abundant bio-resources available for performance-cost-benefit applications. For this study, the aforementioned fibers were added to pure polyurethane foam and the properties were investigated based on mechanical (tensile, split tear, elongation, resilience, compression set, and hardness), thermal (thermogravimetric and differential scanning calorimetry), and morphological analyses. These natural fibers were added in wt. % of 1 %, 2.5 %, and 5 % using high shear mixing rates. The closed molded polyurethane foam was prepared using an addition reaction of polyol and isocyanate. The resulting foam composites embedded with natural fibers had uniform color distribution, indicating good fiber dispersion. 1 % fiber loading showed improvements in tensile and resiliency, whereas split tear properties decreased. Moreover, morphological results indicated uniform foaming and dispersion of fillers. This study reinforces the possibility of a more sustainable future by replacing synthetic fillers with natural fillers in industrial applications, including in the automotive, textile, construction, and other leading consumer-based industries.

A new class of polylactic acid (PLA)/polyethylene glycol (PEG) copolymer reinforced with bacterial cellulose nanofibers (BC) was prepared using a solvent casting and particulate leaching methods. Four weight fractions of BC (1, 2.5, 5, and 10 wt%) were incorporated into copolymer via silane coupling agent. Mechanical properties were evaluated using response surface method (RSM) to optimize the impact of pore size, porosity, and BC contents. Compressive strength obtained for PLA/PEG-5 BC wt% was 9.8 MPa, which significantly dropped after developing a porous structure to 4.9 MPa. Nielson model was applied to investigate the BC stress concentration on the PLA/PEG. Likewise, krenche and Hapli-Tasi model were employed to investigate the BC nanofiber reinforcement and BC orientation into PLA/PEG chains. The optimal parameters of the experiment results found to be 5 wt% for BC, 230 μm for pore size, and 80% for porosity. Scanning electron microscopy (SEM) micrograph indicates that uniform pore size and regular pore shape were achieved after an addition of BC-5% into PLA/PEG. The weight loss of copolymer-BC with scaffolds enhanced to the double values, compared with PLA/PEG-BC % without scaffolds. Differential Scanning Calorimetric (DSC) results revealed that the BC nanofiber improved glass transition temperature (T g ) 57 °C, melting temperature (T m ) 171 °C, and crystallinity (χ %) 43% of PLA/PEG reinforced-BC-5%.

The development of synthetic biodegradable polymers using solvent free polymerization has a unique potential to be used as sustainable polymers in biomedical applications. The aim of this work was to synthesize and characterize a sustainable class of poly(lactic acid) (PLA) under different operating conditions via direct polycondensation of lactic acid (LA). Several parameters were tested including the absence of solvents and catalysts on the polymerization, in addition to polymerization temperature and time. Polymerization conditions were evaluated using response surface method (RSM) to optimize the impact of temperature, time, and catalyst. Results showed that molecular weight (Mw) of PLA increased with increasing polymerization time. Highest Mw of 28.4 kD with relatively a broad polydispersity 1.9 was achieved at polymerization temperature 170 °C at 24 h in the free solvent polymerization. This led to a relevant inherent viscosity of 0.37 dl/g. FTIR spectra exhibited a disappearance of the characteristic peak of the hydroxyl group in LA at 3482 cm−1 by increasing the intensity of carbonyl group. The 1H nuclear magnetic resonance (NMR) exhibited the main chain at 5.22 ppm and the signal of methyl proton at 1.61 ppm as well as a signal at 4.33 and 1.5 assigned to the methane proton next to the terminal hydroxyl group and carboxyl group respectively. Meanwhile, the PLA synthesized with a catalyst [Sn(Oct)2] in a free solvent demonstrated comparatively high thermal transition properties of glass transition, melting, and crystallinity temperatures of 48, 106, and 158 °C, respectively. These results are of significant interest to further expand the use of PLA in biomedical applications.

The purpose of this study is to synthesize grafted Bacterial Cellulose (BC) nanofibers using Atom Transfer Radical Polymerization (ATRP) reinforced into poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel matrix. Nanofibers grafting polymerizations were conducted in the presence of the catalyst CuCl/CuBr and the initiator 2-bromoisobutyrylbromide (2-BiBr). Degrees of substitution (DS) of BC-macroinitiators were quantified using both elemental analysis and gravimetric method. FTIR results confirmed BC nanofibers’ surface modifications of both initiator and hydroxyethyl methacrylate (HEMA) grafts. X-ray spectroscopy further confirmed the increase in carbonyl content after PHEMA-grafting polymerization. Results of the gravimetric analysis showed an increase in the weight of the grafted BC upon increasing reaction time. Furthermore, the change in the swelling ratio percentages of the reinforced composites product (BC-MI-3-g-PHEMA-1.5) was considerably higher based on reaction time. Slight increase in the swelling ratio of BC-MI-3 nanofibers was observed after 48 hours to reach 31 %. Moreover, results of thermal gravimetric analysis (TGA) demonstrated that decomposition temperature at 50 % weight loss (T50) decreased to 350 °C for BC-MI-3-g-PHEMA-1.5. These characteristics demonstrate potentials for applications in the biomedical fields including drug delivery and wound care.

Biodegradable copolymers polylactic acid-co-poly ethylene glycol (PLA-co-PEG) were synthesized at a specific volume ratio (PLA/PEG) (80/20) using direct melt polycondensation without solvent. The effects of an oligomeric chain extender (CE) on the mechanical, molecular weight, thermal stability, and degradation were evaluated. The copolymers were tailored by introducing classes of CE contents (0.25, 0.5, 0.075, 1.0, 1.25, and 1.5wt%) (styrene- glycidyl acrylate copolymer). Apparently, the mechanical properties of copolymers were enhanced in the presence of CE. A long chain branch structure has led to a slight improvement of tensile strength to reach 70MPa at CE 1.25%, compared with 60MPa for neat PLA. A significant increase of 17% was observed for the elongation at break of copolymers after addition of CE 1.25%. In addition, the impact strength increased to 7.9KJ/m2 in the ranges of CE 1-1.25%. Melt flow index dramatically reduces with the addition of CE contents. Gas Permeation Chromatography (GPC) showed that the addition of CE 1.25% has resulted in increasing the PLA molecular weight to 132.569kDa with a broad molecular weight distribution, MWD (2.066), and bimodal distribution. Differential Scanning Calorimetric (DSC) results revealed that the chain extension process improved glass transition temperature (Tg) 62°C, melting temperature (Tm) 161°C, and crystallinity (X%) 34.9% as a result of CE 1.25%. Thermal gravimetric analyses (TGA) results indicated that the CEs have a positive effect on the enhancement of thermal stability. Moreover, Scanning Electron Microscopic (SEM) showed that the compatibility and interfacial adhesion between the PLA and PEG chains were enhanced in the existence of the CE contents. The weight loss of the copolymer during 30days of degradation time was 28%, while the weight loss of CE 1.5% was only 3% during the same time interval.

Bipolymer-based mixed matrix membranes (MMMs) have gained great attention for their biomedical applications with improved chemical, thermal, mechanical stability, and engineered morphologies. This chapter discusses the synthesis and characterization of biopolymers applied in membrane. Likewise, it investigates the effect of the biopolymer on the membrane performance. The material advancement in the fabrication of MMMs, predominantly modification of biopolymers and recent developments, are reviewed. Furthermore, the characterization of biopolymer-based MMMs, recent developments and their applications are also explored.

Compressive and fracture toughness have been considered important parameters for evaluating the performance of fiber-reinforced polymers. Natural and synthetic fibers are predominantly used to tailor mechanical and physical properties across a broad range of applications. Natural fiber-reinforced polymers generally possess low mechanical properties compared with synthetic fibers. However, natural fibers are relatively easy to obtain at a high yield and high specific surface area and can be treated chemically to compete with synthetic fibers. A number of factors such as the matrix and fiber selection, fiber dispersion and orientation, and pretreatment of fibers can be used to tailor the mechanical properties of the fiber-reinforced polymer. This chapter presents an overview of work accomplished on the mechanical properties of both natural and synthetic fiber-reinforced polymers. The influence of fracture toughness and the compressive response of natural and synthetic fiber- reinforced polymers are discussed. In addition, the compressive response and failure characteristics of natural and synthetic fibers are reviewed. The hydrophilic nature of fibers leads to reduced compatibility with hydrophobic polymers, which has a negative effect on fracture toughness. Nevertheless, natural fibers open the way toward strong and promising research with an expanding area of potential applications such as nanocomposite materials, paper, biomedical applications, and adsorbent materials.

With increasing carbon dioxide (CO2) emissions from the combustion of fossil-based fuels, the concentration of CO2 in the atmosphere is growing at 407.54[1] parts per million, as released in May 2016. Accordingly, the reduction of CO2 emissions is an essential issue for global climate changes. Tremendous efforts have been directed towards the goal of CO2 separation and capture. These have led to the development of novel classes of porous materials that possess unique potential applications in the capture and sequestration of CO2. Hence, this comprehensive review focuses on studying and analyzing newly developed methods to reduce greenhouse gas emissions and to sequester CO2 released from anthropogenic activities. It compares and analyzes, in terms of storage capacity and adsorption selectivity, the innovative technologies that capture CO2. Also described are the key advancements in CO2 capture from chemical absorption post- and precombustion industrial units and its subsequent physical adsorption by using various zeolites and metal–organic framework (MOF) materials for CO2 adsorption, storage, and separation. Current progress in MOF materials for CO2 capture is considered, and the potentials and limitations of new discoveries in the area are addressed, as it is a rapidly growing area. Furthermore, trends in the design of various kinds of porous structures with tailored macro- and microstructures and target surface properties are examined.

Polymer blends have the potential to be developed into new resins for specific applications with balanced performance properties and economic advantages. In this paper, polypropylene (PP) and linear low-density polyethylene (LLDPE) blends were investigated at specific composition of PP/LLDPE (60/40) blends (PL40) using a Twin Screw Extruder (TSE). The nano-calcium carbonate (CaCO3) content was varied (between 0-40 wt %), and the composites were investigated using slit die rheometers. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques, revealed the existence of favorable interaction between the surface of CaCO3 nanoparticles and PL40 matrices after surface modification of aminopropyltriethoxy silane (AMPTES) coupling agent. Rheological properties reveal that both the apparent viscosity and the pseudo-plasticity of the PL40 nanocomposites increases with increasing nano-CaCO3 contents and decreases slightly by treated nano-CaCO3 with 2% AMPTES. Dynamic mechanical analysis (DMA) demonstrated that the storage modulus (G′) and glass transition temperature (Tg) are enhanced upon treated nano-CaCO3 with a coupling agent. The results from the mechanical properties exhibited that the impact strength was optimum at 20% nano-CaCO3 content, but tensile strength slightly decreased for untreated PL40 nanocomposites. However, treatment with amino coupling agent improved tensile strength. This attribute to the enhancement of dispersion of the nano-CaCO3 particles in PL40 matrix, leading to improved interfacial adhesion. Treatment of nano-CaCO3 significantly improved the Young’s modulus and flexural modulus compared to the untreated PL40 composites. The crystallization behavior of the composites supported the strong interfaces formed on addition of the amino coupling agent. Furthermore, scanning electron microscopic (SEM) showed evidence of improvement in the dispersion of treated CaCO3 in the PL-40 matrix.

Nanobiomaterials are materials with nanometer features that can mimic the dimensions of natural tissues or organs when compared to micron-sized materials, nanobiomaterials exhibit many superior properties including biocompatibility, mechanical, electrical, biodegradability, and optical. Thus, nanobiomaterials have been widely investigated as promising alternative materials for various biomedical and tissue engineering applications. Typically, the organic materials used to create nanocomposite biomaterials are either natural (bacterial cellulose nanofibers and collagen) or synthetic polymers, such as aliphatic polyester, while the most commonly used inorganic material are nanohydroxyapatite, silicate, and carbon nanotube. This chapter aims to bring together a wide variety of organic and inorganic materials combined in certain types of nanocomposite materials for tissue engineering applications. The material choices for the design of scaffolds using nanocomposite systems as well as the fabrication routes to their design are described in this chapter. Details of the processing techniques used to evaluate interfaces in tissue engineering nanocomposite scaffolds are provided.

The aim of this work was to develop novel polyvinyl alcohol (PVA) and polyethylene glycol (PEG) blends hydrogels via solution casting technique followed by γ-irradiation technique to crosslink and form a hydrogel material that contains a certain amount of water when the solution polymer was exposed to γ-radiation at a small dose rate at ambient temperature. The formation of the PVE: PEG cross-linked structure was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) measurement. The degree of swelling increased with increases in PVA content in the PVA-PEG mixed gel. The drug released from the gel material was examined using drug model sodium sulfate. The drug release behavior from the hydrogel networks was influence by the PVA-PEG ratio in the hydrogel preparation. The released amount was influenced dramatically by the ratio of PVA in the initial feed. The kinetic of the drug released from the hydrogels in general was a non-Fickian diffusion type (anomalous) mechanisms, whereas the process is moderately affected by the viscoelastic relaxation of the chains through water penetration. The thermal stability behavior of the hydrogel was demonstrated by thermo-gravimetric analysis (TGA), the tensile strength and compressive strength were found to be increased with increasing PEG content under induced γ-radiation. Furthermore, biodegradability of the PVA: PEG polymer blends were estimated in phosphate buffer solutions (PBS) under different pH values and enzymatic solution at pH 7.4 through weight loss monitoring. The results indicated that the biodegradation was increased as a function of PEG content decreased. The gamma ray crosslinking of the PVA: PEG blend hydrogel can be a good candidate for applications in a drug career.

Polymer blends typically are the most eco- nomical means to develop new resins for specific applica- tions with the best cost/performance balance. In this paper, the mechanical properties, melting, glass transition, and crystallization behavoir of 80 phr polypropylene (PP) with varying weights of linear low density polyethylene (LLDPE) at 10, 20/ 20 wt % CaCO 3, 30, 40, and 50 phr were studied. A variety of physical properties such as tensile strength, impact strength, and flexural strength of these blends were evaluated. The compatibility of these composite was exam- ined by differential scanning calorimetry (DSC) to estimate Tm and Tc, and by dynamic mechanical analysis (DMA) to estimate Tg. The fractographic analysis of these blends was examined by scanning electron microscopy (SEM). It has been confirmed that increasing the LLDPE content trends to decreases the tensile strength and flexural strength. How- ever, increasing the LLDPE content led to increases in the impact strength of PP/LLDPE blends. It was also found that up to 40 phr the corresponding melting point ( Tm) was not effected with increasing LLDPE content. Each compound has more than one T g, which was informed that there is a brittle-ductile transition in fracture nature of these blends, the amount of material plastically deformed on the failure surface seems to increase with the increasing the LLDPE content. And PP/LLDPE blends at temperature (23 � C) showed a ductile fracture mode characterized by the co-ex- istence of a shear yielding process; whereas at lower tem- perature ( y20 � C) the fractured surfaces of specimens appear completely brittle. The specimens broke into two pieces with no evidence of stress whitening, permanent macroscopic deformation or yielding. V C 2011 Wiley Periodi- cals, Inc. J Appl Polym Sci 121: 2413-2421, 2011