Glycerol Succinate Research Articles

Synthesis and Characterization of Poly(glycerol sebacate), Poly(glycerol succinate) and Poly(glycerol sebacate-co-succinate)

In recent years, thermoset elastomers, particularly polyesters derived from the polycondensation of glycerol and non-toxic diacids, have garnered significant interest. This study focuses on the synthesis of poly(glycerol-co-diacids) polymers using varying molar ratios of glycerol (G), sebacic acid (S), and succinic acid (Su). Seven distinct ratios were investigated (PGS (1:1), PGSSu (1:0.9:0.1), PGSSu (1:0.8:0.2), PGSSu (1:0.5:0.5), PGSSu (1:0.2:0.8), PGSSu (1:0.1:0.9) and PGSu (1:1)). The resulting polymers were analyzed using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analyses (DMA), tensile tests, scanning electron microscopy (SEM), gel fraction and degree of swelling determination. Among the synthesized polymers, PGS (1:1) and PGSu (1:1) exhibited superior mechanical robustness than the polymers obtained by mixing diacids. The results show that the incorporation of succinic acid in the synthesis of the polymers progressively led to rougher surfaces and a reduction in thermal resistance compared to PGS (1:1). PGSu (1:1) showed the highest surface roughness and the lowest thermal resistance. The glass transition temperature (Tg) for these elastomers ranged from − 30 °C to 30 °C. Additionally, higher ratios of succinic acid led to increased polymer density and less degree of swelling. The gel fraction of these polymers ranged from 70 to 95%. PGS (1:1) with the lowest and PGSu (1:1) with the highest gel fraction, respectively.Graphical

Synthesis of Prepolymers of Poly(glycerol-co-diacids) Based on Sebacic and Succinic Acid Mixtures.

In this study, poly(glycerol-co-diacids) prepolymers were produced using different ratios of glycerol (G), sebacic acid (S), and succinic acid (Su) (molar ratios: GS 1:1, GSSu 1:0.9:0.1, GSSu 1:0.8:0.2, GSSu 1:0.5:0.5, GSSu 1:0.2:0.8, GSSu 1:0.1:0.9, GSu 1:1). All polycondensation reactions were performed at 150 °C until reaching a degree of polymerization of ≈55%, inferred by the water volume collected from a reactor. We concluded that the reaction time is correlated with the ratio of diacids used, that is, the increase in succinic acid is proportional to a decrease in the duration of the reaction. In fact, the reaction of poly(glycerol sebacate) (PGS 1:1) is twice as slow as the reaction of poly(glycerol succinate) (PGSu 1:1). The obtained prepolymers were analyzed by electrospray ionization mass spectrometry (ESI-MS) and 1H and 13C nuclear magnetic resonance (NMR). Besides its catalytic influence in poly(glycerol)/ether bond formation, the presence of succinic acid also contributes to a mass growth of ester oligomers, the formation of cyclic structures, a greater number of oligomers detected, and a difference in mass distribution. When compared with PGS (1:1), and even at lower ratios, the prepolymers produced with succinic acid presented mass peak characteristics of oligomer species with a glycerol unit as its end group in higher abundance. Generally, the most abundant oligomers have molecular weights between 400 and 800 g/mol.

Effects of medium chain triglycerides on hepatic fatty acid oxidation in clofibrate-fed newborn piglets.

To investigate whether increasing tricarboxylic acid (TCA) cycle activity and ketogenic capacity would augment fatty acid (FA) oxidation induced by the peroxisome proliferator-activated receptor-alpha (PPARα) agonist clofibrate, suckling newborn piglets (n=54) were assigned to 8 groups following a 2 (±clofibrate)×4 (glycerol succinate [SUC], triglycerides of 2-methylpentanoic acid [T2M], valeric acid [TC5] and hexanoic acid [TC6]) factorial design. Each group was fed an isocaloric milk formula containing either 0% or 0.35% clofibrate (wt/wt, dry matter basis) with 5% SUC, T2M, TC5 or TC6 for 5d. Another 6 pigs served as newborn controls. Fatty acid oxidation was examined in fresh homogenates of liver collected on d 6 using [1-14C] palmitic acid (1 mM) as a substrate (0.265μCi/μmol). Measurements were performed in the absence or presence of L-carnitine (1mM) or inhibitors of 3-hydroxy-3-methylglutaryl-CoA synthase (L659699, 1.6μM) or acetoacetate-CoA deacylase (iodoacetamide, 50μM). Without clofibrate stimulation, 14C accumulation in CO2 was higher from piglets fed diets containing T2M and TC5 than SUC, but similar to those fed TC6. Under clofibrate stimulation, accumulation also was higher in homogenates from piglets fed TC5 than all other dietary treatments. Interactions between clofibrate and carnitine or the inhibitors were observed (P=0.0004) for acid soluble products (ASP). Invitro addition of carnitine increased 14C-ASP (P<0.0001) above all other treatments, regardless of clofibrate treatment. The percentage of 14C in CO2 was higher (P=0.0023) in TC5 than in the control group. From these results we suggest that dietary supplementation of anaplerotic and ketogenic FA could impact FA oxidation and modify the metabolism of acetyl-CoA (product of β-oxidation) via alteration of TCA cycle activity, but the modification has no significant impact on the hepatic FA oxidative capacity induced by PPARα. In addition, the availability of carnitine is a critical element to maintain FA oxidation during the neonatal period.

Synthesis and hydrolytic degradation of poly (glycerol succinate) based polyesters

The limited availability of petroleum resources motivates the research towards value-added products production from bio-resources. This study reports the synthesis of glycerol and succinic acid-based polyesters and their detailed characterization. The modification of poly (glycerol succinate) was done by using other diacids like glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedioic acid. The sysnthesized polyesters were characterized using various techniques such as thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The addition of different dicarboxylic acids to poly (glycerol succinate) based co-polyesters increased the thermal stability of poly (Glycerol succinate). Glass transition temperatures were obtained in the range of −17.2 to −22.5 °C and it increased with chain length. The progress of reaction was monitored by determining acid number, ester number, and degree of esterification. The hydrolytic degradation of polyesters was carried out in acidic and basic medium. The polyesters was found to degrade under basic conditions whereas no weight loss of poly (glycerol succinate) was found under acidic conditions. Particularly, about 40% of poly (glycerol succinate) was degraded within 24 h under basic conditions (pH = 12). The analysis of morphology of polyesters during degradation showed that the increase in hydrolysis time increased the heterogeneity in polyester matrix.

Poly(Glycerol Succinate) as Coating Material for 1393 Bioactive Glass Porous Scaffolds for Tissue Engineering Applications.

Aliphatic polyesters are widely used for biomedical, pharmaceutical and environmental applications due to their high biodegradability and cost-effective production. Recently, star and hyperbranched polyesters based on glycerol and ω-carboxy fatty diacids have gained considerable interest. Succinic acid and bio-based diacids similar to glycerol are regarded as safe materials according to the US Food and Drug Administration (FDA). Bioactive glass scaffolds utilized in bone tissue engineering are relatively brittle materials. However, their mechanical properties can be improved by using polymer coatings that can further control their degradation rate, tailor their biocompatibility and enhance their performance. The purpose of this study is to explore a new biopolyester poly(glycerol succinate) (PGSuc) reinforced with mesoporous bioactive nanoparticles (MSNs) as a novel coating material to produce hybrid scaffolds for bone tissue engineering. Bioactive glass scaffolds were coated with neat PGSuc, PGSuc loaded with dexamethasone sodium phosphate (DexSP) and PGSuc loaded with DexSP-laden MSNs. The physicochemical, mechanical and biological properties of the scaffolds were also evaluated. Preliminary data are provided showing that polymer coatings with and without MSNs improved the physicochemical properties of the 1393 bioactive glass scaffolds and increased the ALP activity and alizarin red staining, suggesting osteogenic differentiation potential when cultured with adipose-derived mesenchymal stem cells. PGSuc with incorporated MSNs coated onto 1393 bioactive glass scaffolds could be promising candidates in bone tissue engineering applications.

Development of Flexible Nanocomposites Based on Poly(ε-caprolactone) for Tissue Engineering Application: The Contributing Role of Poly(glycerol succinic acid) and Polypyrrole

Poly(ε-caprolactone) (PCL), a semi-crystalline polyester, has been widely used for tissue engineering and regenerative medicine applications due to its favorable mechanical properties, biocompatibility, and long-term biodegradation. Despite desirable physical and chemical characteristics, PCL shows low hydrophilicity, thus constraining its utility for biomedical applications. Here, we report the synthesis and characterization of elastomeric PCL/poly(glycerol succinate) (PGSu) blends and their nanocomposites with improved surface wettability and tunable mechanical properties, and controlled biodegradation. Also, the effect of the polypyrrole (PPy) coating layer on the properties of scaffolds was investigated. By tailoring the surface and bulk properties of scaffolds using a change in PCL to PGSu ratio, adding nano-hydroxyapatite (n-HA) as a filler, and deposition of PPy on the scaffolds, it is possible to engineer scaffolds with customized degradation and mechanical properties. The addition of PGSu and n-HA increased hydrophilicity of the PCL matrix, developed its mechanical performance, and enhanced in-vitro cell metabolic activity. It was shown that Young’s modulus of PCL-PGSu-based scaffolds could be tuned from about 11.5 MPa to 4.5 MPa by altering the amount of PGSu and n-HA within the PCL network. The crystallinity of PCL was also considerably influenced by PGSu and n-HA. Moreover, deposition of PPy on the scaffolds resulted in a desirable antibacterial activity and electrical conductivity of about 5*10-2 S/cm. As expected, the rate of degradation increased with an increase in PGSu concentration. At the same time, the PPy coating layer delayed the degradation process, indicating that the biodegradation rate of the PCL matrix can be regulated. PCL-PGSu-based scaffolds also supported cell viability and proliferation, where PPy coating significantly improved cell viability. Therefore, the synthesized scaffolds can be used for a range of tissue engineering applications.

Glycerol-based polymer adhesives reinforced with cellulose nanocrystals

Biodegradable adhesives are of great scientific and technological interest as an alternative to conventional commercial products, which generally can release toxic substances and take a long time to degrade. Composites using biodegradable polymers synthesized by polycondensation of glycerol and diacids, i.e., poly(glycerol succinate), PGSu, poly(glycerol maleate), PGM, and poly(glycerol maleate-co-succinate), PGMSu, reinforced with cellulose nanocrystals (CNC) were used as adhesives for Angelim ( Vatairea heteroptera Ducke ). CNC were added at 0, 5, 10 and 20 wt% to the glycerol-derived polymers in order to evaluate their effect on mechanical properties. Polymers and composites were analyzed by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). Adhesive joints were prepared using the synthesized glycerol-based polymers, and poly(vinyl acetate), PVAc, for comparison purposes. Thermal analyses indicated that most of the glycerol-based polymers tested are stable up to 260 °C while adhesion tests indicated that adhesives containing CNC showed superior shear strength as compared to pristine polymers and PVAc. These results suggest that the addition of cellulose nanocrystals (CNC) is a viable approach to tailor the mechanical and adhesive properties. • Biodegradable adhesives are a new generation of adhesives with tailored adhesion and degradation. • Cellulose nanocrystals (CNC) are widely used due to their aspect ratio, crystallinity, mechanical properties and biodegradability. • The combination of glycerol polymers with CNC improves mechanical properties and controls degradation time to produce tailor-made adhesives. • These adhesives can be a viable alternative to using larger amounts of glycerol and adding value to a by-product of the biodiesel production market.

Mathematically described preparation process of poly(glycerol succinate) resins and elastomers—Meeting science with industry

We created polyester, which building blocks naturally occur in the human organism: glycerol and succinic acid. A process of preparation of poly(glycerol succinate) resins and its purification was developed. The resins were obtained in a polycondensation reaction with the monomer being prepared in situ. Due to that, succinic anhydride and glycerol were used as reaction substrates. The obtained resins were next crosslinked toelastomers. Mathematical models described both processes for the first time in the case of poly(glycerol succinate). Such models are allowing for defining the process parameters to obtain a material with desired properties. For example, optimal conditions for resins synthesis were estimated, and requirements for yielding elastomer with Tg in range −10 to 40°C could be determined based on our second model. Such a novel approach combines science with industry needs, where knowledge of processes is key to success. Also, it has to be said that glycerol, which is a waste of biodiesel production, could be used in our process, but we recommend prior purification.

Poly(Glycerol Succinate) as an Eco-Friendly Component of PLLA and PLCL Fibres towards Medical Applications.

This study was conducted as a first step in obtaining eco-friendly fibres for medical applications using a synthesised oligomer poly(glycerol succinate) (PGSu) as an additive for synthetic poly(L-lactic acid) (PLLA) and poly (L-lactide-co-caprolactone) (PLCL). The effects of the oligomer on the structure formation, morphology, crystallisation behaviour, and mechanical properties of electrospun bicomponent fibres were investigated. Nonwovens were investigated by means of scanning electron microscopy (SEM), wide angle X-ray scattering (WAXS), differential scanning calorimetry (DSC), and mechanical testing. The molecular structure of PLLA fibres is influenced by the presence of PGSu mainly acting as an enhancer of molecular orientation. In the case of semicrystalline PLCL, chain mobility was enhanced by the presence of PGSu molecules, and the crystallinity of bicomponent fibres increased in relation to that of pure PLCL. The mechanical properties of bicomponent fibres were influenced by the level of PGSu present and the extent of crystal formation of the main component. An in vitro study conducted using L929 cells confirmed the biocompatible character of all bicomponent fibres.

Enzymatic Synthesis of Biodegradable Polyesters using Succinic Acid Monomer Derived from Cellulose of Oil Palm Empty Fruit Bunch

Oil palm empty fruit bunch fiber (OPEFB) is a lignocellulosic waste from palm oil mills. It is a potential source of glucose and xylose that can be used as raw materials for the production of valuable compounds such as succinic acid. The present study aims at producing biodegradable polyesters from OPEFB-derived monomer using enzymatic polymerization. Cellulose was extracted from OPEFB by using organosolv method. Enzymatic hydrolysis of cellulose was carried out using Celluclast and Novozyme 188 at 40 °C, with agitation rate of 145 rpm. Amount of enzyme and cellulose as well as reaction time were varied. The highest glucose concentration produced was 167.4 g/L. Succinic acid was produced when glucose was subjected to fermentation using Actinobacillus succinogenes with the highest concentration of 23.50 g/L. Biodegradable polyesters were produced when succinic acid together with 1,4-butanediol, glycerol and ethylene glycol, respectively, were subjected to Lipase (Candida Antartica CALB). Molecular weight obtained for poly(butylene succinate), poly(glycerol succinate), and poly(ethylene succinate) were 5.90 × 104, 6.20 × 104, and 4.53 × 104 g/mol, respectively. The greatest extent of biodegradability of polyester found was 78.65 ± 0.65%.

Study of bio-synthesised transition nano metal oxides dispersed polyester composites as enhanced protectors for mild steel in 0.5 M H2SO4 medium-a green approach

A facile, efficient and eco-friendly synthesis of transition nano metal oxides like zinc oxide (ZnO), copper oxide (CuO), tin oxide (SnO) from Persea americana. Mill was executed followed by ex-situ polymerization favoring poly (glycerol succinate) (PGS)/nano metal oxide composite for the first time. The incorporation of nanofillers was confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction spectrometer (XRD), Scanning electron microscopy (SEM) and Energy dispersive spectroscopy (EDS). As a comparative approach, the extent of metal dissolution was evaluated in presence of precursor as well as nano dispersed forms for various concentrations (10, 50, 100, 500, 1000 ppm) under the cluster of electrochemical and non-electrochemical techniques. Enhanced inhibition efficiency of 97% was observed in the case of CuO dispersion which was additionally supported by XRD particle size determination. The increase in charge transfer resistance (Rct) and a decrease in corrosion current (Icorr) elicited from electrochemical measurements strictly proved the role of metal – oxide nanoparticles. Further, the mode of inhibitor was found to be predominantly cathodic.

Effects of Dietary Anaplerotic Carbon Sources and Ketogenic Fatty Acids on Hepatic Fatty Acid Oxidation in Neonatal Pigs

Feeding clofibrate (a PPARα pharmaceutical agonist) to newborn pigs greatly increases hepatic fatty acid oxidation by stimulating the activities of the key enzymes (CPTI and HMGCS) in β‐oxidation and ketogenesis. This study was conducted to investigate whether increasing Krebs cycle activity and ketogenic capacity would benefit the fatty acid oxidation induced by the PPARα agonist. Suckling newborn pigs (N=48) from 6 litters were assigned randomly into 8 treatment groups based on body weight (1.31±.2 kg) following a 2 (± clofibrate) × 4 (+succinate, valerate, hexonate or 2‐methylpentanoate (2MPA)) factorial design. Pigs were fed a basal milk replacer containing either 0 or 0.35% of clofibrate with supplementation of 5% glycerol‐succinate (GS), triglycerides of valerate (triC5), hexanate (triC6), or 2MPA (tri2MPA). As supplemented, milk formula were isocaloric and given to the pigs 3Xper d for 5 d. Fatty acid oxidation was examined in fresh homogenates of liver collected on d 6 using [1‐14C] palmitic acid (1 mM). The measurements were performed in the absence or presence of carnitine (1mM) or L659699 (1.6 μM), inhibitor of 3‐hydroxy‐3‐methylglutaryl‐CoA synthase, and iodoacetamide (50 μM) inhibitor of acetoacetate synthesis. Total hepatic palmitate oxidation (14C accumulated in CO2 and acid soluble products (ASP)) was on average 2.2 fold higher from pigs fed clofibrate than without clofibrate (P &lt; 0.0001). Supplementation of GS, triC5, triC6 or tri2MPA to the diets had no significantly impacts on the hepatic palmitate oxidation (P = 0.57). However, the dietary treatments significantly changed the distributions of 14C accumulation between in CO2 and ASP regardless of clofibrate supplementation. The 14C accumulation in CO2 in homogenates from pigs fed tri2MPA without clofibrate was 72% and 57% higher than in homogenates from pigs fed GS and triC5 (P&lt;0.006). Liver homogenates from pigs fed triC6 also had higher 14C accumulation in CO2 compared with pigs fed GS. No difference was detected between tri2MPA and triC6 treatments. Clofibrate increased 14C accumulation in CO2 in pigs fed all diets (P &gt; 0.0001), but the increase was greater from pigs fed diets containing triC6, triC5 and GS than tri2MPA (P&lt;0.0001). No differences were observed among pigs fed triC6, triC5 and GS. Inclusion of carnitine in the incubations increased 14C accumulation in both CO2 and ASP by 2.6 fold in pigs, regardless of clofibrate treatment. Addition of either L659699 or iodoacetamide had no impact palmitate oxidation rate. The results indicate that dietary supplementation of extra anaplerotic carbon sources and ketogenic fatty acids modifies the metabolism of acetyl‐CoA (product of β‐oxidation) via changing TCA cycle activity, but the modification has no impact on the hepatic fatty acid oxidative capacity induced by PPARα activation. The availability of carnitine in the milk is a key element to maintain robust fatty acid oxidation rate during the neonatal period.Support or Funding InformationSupported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2015‐67015‐23245

Effect of Medium Chain Triglycerides on TCA and Ketogenic Capacity of Proximal Intestinal Fatty Acid Oxidation in Clofibrate Feed Newborn Pigs

Newborn pigs are much less efficient at utilizing milk fat as an energy source, than weaned pigs, due to a limited capacity of fatty acid oxidation. We have previously shown that clofibrate, a PPARα agonist, increases fatty acid oxidation levels in newborn pigs by increasing production of key metabolic enzymes. We hypothesize that feeding anaplerotic carbon sources or ketogenic fatty acids in conjunction with clofibrate will improve energy utilization in young pigs by increasing capacities of the TCA cycle or ketogenic activity. To test our hypothesis, suckling newborn pigs (N=48) from 6 litters, which received colostrum for 24 hours, from the North Carolina State University Swine Unit were randomly divided into a 2 (control vs clofibrate) × 4 (glycerol‐succinate, valerate, hexonoate, 2‐methylpentanoate) factorial design. All piglets were fed a standard milk replacer three times a day based on body weight (1.31±.2kg). All supplements, glycerol‐succinate (GS), triglycerides of valeric acid (triC5), hexanoic acid (triC6) or tri‐2‐methylpentanoate (2‐MPA), were fed at ~5% (w/w as fed to maintain an isocaloric diet). For the clofibrate treatment groups, clofibrate was included (.35%) only in the morning feedings. Milk was withheld on the sixth day when the mucosa was collected from the proximal small intestine. The mucosa (28.43±6.12 mg/mL protein) was homogenized and added to flasks that contained a buffer without (control) or with carnitine (1mM), L659699 (1.6 μM), or iodoacetamide (50 μM) and labeled [1–14C] palmitic acid (1mM) as the substrate. L659599 is an inhibitor of both mitochondria and cytosolic hydroxymethylglutaryl‐CoA synthase and iodoacetamide is an inhibitor of acetoacetate synthesis. After 30 mins, the reactions were terminated and 14C accumulation in CO2 and acid soluble products (ASP) was measured to determine fatty acid oxidation rates. The oxidation of palmitic acid (14C accumulations in CO2 +ASP; μmol/h.mg protein) was higher (P &lt; 0.0001) in the pigs that received triC5 (1.54) and triC6 (1.51) than those that received GS (1.27) or 2‐MPA (1.47). No differences were detected between pigs receiving triC5 and triC6 or between GS and 2‐MPA. Clofibrate had no effects on the palmitic acid oxidation from pigs fed GS or triC6, but the 14C accumulation in CO2 and ASP was increased by 40% and 26% in pigs receiving triC5 and 2‐MPA (P &lt;0.0003), respectively. Addition of carnitine with or without clofibrate increased palmitic acid oxidation by 44% as compared with the control (P &lt; 0.0001), while oxidation was reduced by 9% by L659699 (P &lt; 0.004). Oxidation rates in incubations with iodoacetamide were higher than with L659699 (P &lt; 0.03), but were not different from controls (P =0.92). The results indicate that fatty acid oxidation in the mucosa of the proximal small intestine of newborn pigs could be increased by enhancing ketogenic activity and TCA cycle capacity, thus demonstrating that dietary supplementation of ketogenic fatty acid and anaplerotic carbon would be favorable to improve milk fat utilization in pigs during the postnatal period.Support or Funding InformationSupported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, under award number 2015‐67015‐23245.

Impact of Butyl Glycidyl Ether Comonomer on Poly(glycerol–succinate) Architecture and Dynamics for Multifunctional Hyperbranched Polymer Design

An original strategy is proposed to easily design functional materials from poly(glycerol–succinate) (PGS). This approach consists in the introduction of an epoxidized functional agent during the polyesterification between the glycerol and succinic acid. In order to model the effect of this epoxide group on the polymerization process and its resulting hyperbranched architecture, the butyl glycidyl ether (BGE) has been selected as comonomer agent. The theoretical potential reactions have been confronted with the topological units revealed by 2D NMR correlations. The regioselectivity against the primary alcohol and the stoichiometric balance of the system have been modified in situ by the kinetic control of parallel reactions. This had the effect to delay the gelation and increase the polyesterification conversion. The resulting hyperbranched polymers (HBPs) obtained just after gelation exhibit a temperature of glass transition (Tg) of −3.9 °C for PGS and −16.1 °C for poly(glycerol–succinate-co-butyl glycid...

Synthesis of Glycerol-Based Biopolyesters as Toughness Enhancers for Polylactic Acid Bioplastic through Reactive Extrusion.

The synthesis of polyesters based on glycerol, succinic acid [poly(glycerol succinate), PGS] and/or maleic anhydride [poly(glycerol succinate-co-maleate), PGSMA] was investigated aiming to produce a green product suitable for toughening of polylactic acid (PLA) using melt blending technologies. The molar ratio of reactants and the synthesis temperature were screened to find optimum synthesis conditions leading to the highest toughness enhancement of PLA. It was found that a molar ratio of reactants of 1:1 glycerol/succinic acid increases the effectiveness of PGS as a toughening agent for PLA, which correlates with the achievement of a higher molecular weight on the synthesis of PGS. The introduction of maleic anhydride as a comonomer for the synthesis of the partial replacement of succinic acid was advantageous for making PGS suitable for reactive extrusion (REX) mediated by free radical initiators. The tensile toughness of the REX PLA/PGSMA blends was improved by 392% compared with that of neat PLA, which was caused by the simultaneous cross-linking of PGSMA within the PLA matrix, and the in situ formation of PLA-g-PGSMA graft copolymers acting as interfacial compatibilizers. Two-dimensional nuclear magnetic resonance and Fourier transform infrared analysis confirmed the formation of PLA-g-PGSMA species on REX experiments. This in turn caused a decrease in the diameter of the PGS particles dispersed within the PLA matrix from >10 μm to approximately 2 μm as observed using scanning electron microscopy. A further increase of 1600% in the toughness of the blends was achieved by lowering the synthesis temperature of PGSMA from 180 to 150 °C. The optimum synthesis conditions for PGSMA leading to the highest increase in the toughness of 80/20 PLA/PGSMA blends were found to be 1:0.5:0.5 mol glycerol/succinic acid/maleic anhydride synthesized at a temperature of 150 °C for 5 h.

Characterisation of poly(glycerol-succinate) oligomers as bio-based non-ionic surfactants by nuclear magnetic resonance and mass spectrometry

Naturally derived non-ionic surfactants of poly(glycerol-succinate), PGS, Grafted PGS and PGS-sorbitan oligoester surfactants were synthesized and characterized by quantitative nuclear magnetic resonance (13C NMR), qualitative liquid chromatography–mass spectrometry (LC–MS) and fourier transfer infarred (FTIR). LC–MS is used to study the components in two different conditions, and the spectrum data in acidic condition reveals an average of three-four glycerol-succinate (GS) repeat units of PGS oligoester. Acidic condition (condition I) also reveals PGS-sorbitan oligoester with an average of three glycerol-succinate (GS) repeat units (calcd. mass 910 Da), while neutral condition (condition II) is revealed to distribute approximately evenly among short PGS branches and longest PGSs. Using LC in reverse-phase mode with two different mobile system, the PGS oligomers of the nonionic surfactant were observed the detailed characterisation of their compositions and structures in agreement with mathematic models from the data of quantitative 13C NMR. Their self-assembly in aqueous solution was studied using fluorescence spectroscopy and their foamability was evaluated. The critical aggregation concentration (CAC) ranged from 0.447 to 0.126 mM.