Liquefied biomass derived plasticizer for polylactide

BACKGROUND: The valorization of renewable agro‐industrial residues and their further utilization for production of polymers and polymer additives is a highly attractive alternative for replacement of oil‐based materials. RESULTS: Liquefied wood flour and rice bran derived esters were synthesized and evaluated as novel green plasticizers for polylactide (PLA). The liquefied wood flour ester (PWF) showed good miscibility with PLA and good plasticization efficiency as shown by differential scanning calorimetry (DSC) and tensile testing. Tensile strain at break increased from a few percent for pure PLA to over 100 and 300% for the materials containing 10 and 30 wt‐% of PWF. The addition of PWF accelerated the hydrolysis rate of PLA as shown by faster weight loss during aging in water and faster formation of water‐soluble lactic acid oligomers, which was shown by electrospray ionization mass spectrometry (ESI‐MS) analysis of the migrants. The liquefied rice bran based product (PRB) was not miscible with PLA and it did not improve the elongation at break of PLA. Rice bran is generally rich in arabinoxylans with only secondary less reactive alcohol groups. The larger number of un‐reacted hydroxyl‐groups in PRB was confirmed by Fourier transform infrared (FTIR) spectroscopy and could explain the immiscibility with PLA. CONCLUSIONS: The results demonstrate that the synthesized liquefied wood flour derived plasticizer could have great potential as a biobased polylactide plasticizer. © 2012 Society of Chemical Industry     

Citrate esters as plasticizers for poly(lactic acid)

Citrate esters were used as plasticizers with poly(lactic acid) (PLA). Films were extruded using a single-screw extruder with plasticizer contents of 10, 20, and 30% by weight. All of the citrate esters investigated were found to be effective in reducing the glass transition temperature and improving the elongation at break. It was observed that the plasticizing efficiency was higher for the intermediate-molecular-weight plasticizers. Hydrolytic and enzymatic degradation tests were conducted on these films. It was found that the lower-molecular-weight citrates increased the enzymatic degradation rate of PLA and the higher-molecular-weight citrates decreased the degradation rate as compared with that of unplasticized PLA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1507–1513, 1997     

Poly(vinyl chloride) films plasticized with novel poly‐nadic‐anhydride polyester plasticizers

In this work, several novel poly‐nadic‐anhydride polyester plasticizers were developed to be used in poly(vinyl chloride) (PVC) film fabrication for the first time. Mechanical properties of the films, the compatibility of plasticizers in PVC resin, as well as testing of migration of the plasticizers, were performed in order to evaluate the efficiency of plasticization. Scanning electron microscopy, Fourier‐transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry were used to characterize the unplasticized and plasticized polymer. The results demonstrated that the as‐prepared poly‐nadic‐anhydride plasticized PVC film significantly improved the plasticization efficiency of PVC film based on the increase in the break in elongation of the films. According to scanning electron microscopy analysis, the poly‐nadic‐anhydride polyester plasticizers presented good compatibility with PVC resin. In volatility and extraction tests, PVC films plasticized with the poly‐nadic‐anhydrides showed enhanced migration resistance. The plasticizing effects induced by the poly‐nadic‐anhydride polyester plasticizers were also confirmed by a glass transition temperature shift toward lower temperatures in the plasticized films. J. VINYL ADDIT. TECHNOL., 23:321–328, 2017. © 2015 Society of Plastics Engineers     

Synthesis and characterization of biobased polyester PVC plasticizers to industrial manufacturing of tubes

The search for the substitution of phthalate derivatives in the process of polyvinyl chloride (PVC) plasticization is a matter of intensive research, due to the increasing proofs about phthalate toxicity. With this objective, a series of novel saturated polyesters (SPs) were synthesized by polycondensation from different biobased acids and diols, and end-capped with 2-tetradecyloctadecan-1-ol (TDOD). After characterization, the SPs were incorporated in an industrial formulation for flexible PVC and the mechanical properties of the films analyzed by tensile tests, DMTA, and DSC. The tensile tests revealed a similar ultimate tensile strength and a higher elongation at break for the PVC with SP as plasticizers compared with DEHTP (di[2-ethylhexyl] terephthalate). The SP showing the most promising results was chosen to carry on an industrial manufacturing of a transparent tube. The migration tests of the tube show a much less leaching properties compared with tube prepared using the plasticizer DEHTP. All the results indicate that SPs can be an industrially viable and excellent alternative to DEHTP.     

Plasticizing effect of poly(ethylene glycol)s with different molecular weights in poly(lactic acid)/starch blends

Binary and ternary blends composed of poly(lactic acid) (PLA), starch, and poly(ethylene glycols) (PEGs) with different molecular weights (weight‐average molecular weights = 300, 2000, 4000, 6000, and 10, 000 g/mol) were prepared, and the plasticizing effect and miscibility of PEGs in poly(lactic acid)/starch (PTPS) or PLA were intensively studied. The results indicate that the PEGs were effective plasticizers for the PTPS blends. The small‐molecule plasticizers of PEG300 (i.e., the M_w of PEG was 300g/mol) and glycerol presented better plasticizing effects, whereas its migration and limited miscibility resulted in significant decreases in the water resistance and elongation at break. PEG2000, with a moderate molecular weight, was partially miscible in sample PTPS3; this led to better performance in water resistance and mechanical properties. For higher molecular weight PEG, its plasticization for both starch and PLA was depressed, and visible phase separation also occurred, especially for PTPS6. It was also found that the presence of PEG significantly decreased the glass‐transition temperature and accelerated the crystallization of the PLA matrix, depending on the PEG molecular weight and concentration. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41808.     

Palm oil deodorizer distillate as toughening agent in polylactide packaging films

Polylactide (PLA) is the most used biodegradable and biobased food packaging polymer for rigid containers and films. However, its low ductility is a hurdle for increasing its applications in flexible food packaging. A solution is the use of additives. Palm oil deodorizer distillate (PODC) is revealed to be an excellent additive promoting PLA ductility. PODC is a by‐product of vegetable oil refining, which is available in stable quality and in sufficient amounts. Amorphous PLA/PODC blends had an elongation at break of around 130% and that of semi‐crystalline blends was still around 55% compared to the initial 5% of neat PLA. At the same time the PLA rigidity and high glass transition temperatures were kept. PODC was also a very efficient processing aid, allowing for film blow extrusion. The blends were stable in properties during six months without exudation. They complied with legal norms of Food Contact Materials (EU 10/2011) and induced no sensorial alteration of packed food. Therefore PODC is a very interesting alternative to common plasticizers for the production of flexible PLA packaging films. © 2016 Society of Chemical Industry     

明胶蛋白质基可降解塑料薄膜的研究

将分散均匀的明胶、无机填料和复合增塑剂的水溶液用流延法成膜,制得了蛋白质基可降解塑料薄膜。用拉伸实验、吸水实验和降解实验表征了蛋白质基可降解塑料薄膜的性能。结果表明:薄膜的拉伸强度和断裂伸长率随增塑剂用量的增加而增加,随无机填料用量的增加而减小;薄膜的耐水性随增塑剂用量的增加而变差;蛋白质基塑料薄膜具有生物降解性,在20天内降解度为10%左右。     

Esters of Cinnamic Acid as Green Plasticizers for Polylactide Formulations with Improved Ductility

This study demonstrates the potential of different cinnamate esters, namely methyl trans-cinnamate (MC), isobutyl cinnamate (IBC), allyl cinnamate (AC), and ethyl cinnamate (EC), as environmentally friendly plasticizers for polylactide (PLA). Plasticized PLA formulations with a constant nominal wt% of 20 of each plasticizer are compounded in a twin-screw co-rotating extruder and subsequently processed by injection molding. The results show exceptional plasticization efficiency of AC with an increase in elongation at break from 3.9% (neat PLA), up to 339.4% and a remarkable increase in impact strength, thus showing great potential to overcome the main drawback related to PLA intrinsic brittleness. The incorporation of cinnamates in a PLA matrix leads to a decrease in T_g from 61.7 °C down to 36.1 °C for the plasticized PLA formulation containing 20 wt% AC. Thermogravimetry analysis reveals that a slight plasticizer loss occurs during processing, as it happens with other monomeric plasticizers, but this phenomenon does not limit their plasticization efficiency. Therefore, the results obtained in this study confirm the suitability of a new family of organic compounds derived from the esterification of cinnamic acid as green plasticizers for PLA with improved toughness, with comparable, or even superior, ductile properties of typical plasticizers for PLA.     

Effect of mixing poly(lactic acid) with glycidyl methacrylate grafted poly(ethylene octene) on optical and mechanical properties of the blown films

Poly(lactic acid) (PLA) was plasticized with acetyl tributyl citrate (ATBC). The plasticized PLA was further blended with poly(ethylene octene) grafted with glycidyl methacrylate (POE‐g‐GMA denoted as GPOE) using a twin‐screw extruder and the extruded samples were blown using the blown thin film technique. Both ATBC and GPOE significantly influenced the physical properties of the films. Compared to neat PLA, the elongation at break and tear strength of the films were significantly improved. The cavitation and large plastic deformation observed in films subjected to the tear test were the important energy‐dissipation process, which led to a torn PLA film. Moreover, the PLA/ATBC/GPOE blown films had better transparency and water tolerance than that of neat PLA. GPOE could act as a tear resistance modifier for PLA blown films. These findings contributed new knowledge to the additives area and gave important implications for designing and manufacturing polymer packaging materials. POLYM. ENG. SCI., 55:2801–2813, 2015. © 2015 Society of Plastics Engineers     

Epoxidized soybean oil‐plasticized poly(lactic acid) films performance as impacted by storage

This study examined the effect of storage time at room temperature on the melt viscosity, thermal, and tensile properties of epoxidized soybean oil plasticized poly(lactic acid) (PLA) films manufactured through a cast extrusion process. Infrared results indicate that plasticizer migration to the surface of the film occurred after only 30 days of storage, which significantly affected the performance of plasticized films. While the melt viscosity, glass transition temperature, degree of crystallinity, tensile strength, and modulus increased, the elongation at break and energy to break decreased with storage time up to 30 days and all properties remained constant thereafter. However, the ability of stored plasticized film to cold crystallize remained unaffected since both the cold crystallization temperature and melting temperature were not affected during storage. Although plasticized film lost some flexibility after only 30 days of storage due to plasticizer migration to the surface of the film, sufficient plasticization performance still remained in plasticized PLA films for flexible packaging application even after a long storage period at ambient conditions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43201.     

Evaluation of some eco‐friendly plasticizers for PLA films processing

This study was conducted as a first step in order to obtain green materials for food packaging by using an eco‐friendly bioplastic, polylactic acid (PLA), and nontoxic plasticizers. Different types of nontoxic biocompatible plasticizers/lubricants, both obtained in the laboratory, as well as commercial ones, were employed to modulate physical and mechanical properties of PLA. Melt compounding by means of a Brabender mixer led to obtaining of homogeneous materials. The incorporation of PLA oligomer, l ‐lactide, poly(ethylene glycol), and epoxidized soybean oil (USE) improved the melt flow and processability, increasing the hydrophilicity of the resulted plasticized PLA systems. USE significantly increased the elongation at break, reduced the glass transition temperature, and increased the PLA chain mobility. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43223.     

Plasticizing polylactide—the effect of different plasticizers on the mechanical properties

Poly(lactide) (PLA), a biodegradable aliphatic polyester with excellent property profiles for different polymer applications, will play a major role in future markets for biodegradable polymers from renewable resources. PLA is a very brittle and stiff polymer with a glass transition temperature of around 58°C. The mechanical properties of PLA are comparable to those of polystyrene, with an elasticity modulus of 3500 MPa, a maximum tensile strength of 50 MPa, and an elongation at break of 4%. To introduce PLA into other applications requiring other mechanical property profiles, especially higher flexibility and higher impact resistance, it is necessary to use plasticizers. In this study the influence of several biocompatible plasticizer systems on the mechanical properties of PLA is determined. Poly(ethylene glycol), glucosemonoesters and partial fatty acid esters are introduced at 2.5, 5, and 10 wt% into polylactide. The mechanical properties, such as impact strength and the stress-strain-interrelationship of tensile tests, show changes, which are discussed.     

The effects of plasticizers on the dynamic mechanical and thermal properties of poly(lactic acid)

Poly(lactic acid) (PLA) was blended with five plasticizers in a batchwise mixer and pressed into films. The films were analyzed by means of dynamic mechanical analysis and differential scanning calorimetry to investigate the properties of the blends. Triacetine and tributyl citrate proved to be effective as plasticizers when blended with PLA. The glass transition temperature of PLA decreased linearly as the plasticizer content was increased. Both plasticizers were miscible with PLA to an extent of ～ 25 wt %. At this point, the PLA seemed to be saturated with plasticizer and the blends tended to phase separate when more plasticizer was added. There were also signs of phase separation occurring in samples heated at 35, 50, and 80°C, most likely because of the material undergoing crystallization. The presence of the plasticizers induced an increased crystallinity by enhancing the molecular mobility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1227–1234, 2002     

Evaluating effects of biobased 2,5‐furandicarboxylate esters as plasticizers on the thermal and mechanical properties of poly (vinyl chloride)

We synthesized 2,5‐furandicarboxylate esters [i.e., dibutylfuran‐2,5‐dicarboxylate, diisoamylfuran‐2,5‐dicarboxylate, and di(2‐ethylhexyl)furan‐2,5‐dicarboxylate] and investigated their potential application as plasticizers of commercial poly(vinyl chloride) (PVC) products. Fourier transform infrared analysis, mechanical tests, scanning electron microscopy investigation, differential scanning calorimetry analysis, dynamic mechanical thermal analysis, thermogravimetric analysis (TGA), melt flow rate (MFR) measurement, and plasticizer migration measurements were used to the evaluate the comprehensive properties of the blended products. The results of the tensile tests demonstrate that the blends exhibited antiplasticization and flexible plastic characteristics at 10 and 50 phr in PVC, respectively. Moreover, flexural and impact test data indicate that the three types of blends exhibited a similar tendency: the hardness decreased continuously as the amount of plasticizer increased. Their morphology indicated that all of the plasticizers had good compatibility with PVC. The resulting glass‐transition temperature of the investigated plasticizers was lower than that of pure PVC, and reduction was largest for the plasticizer with the highest molecular weight. TGA revealed that the thermal degradation of blended polymers occurred in three stages and that all of the blends were stable up to 180°C. Finally, the MFRs of all of the specimens indicated that the addition of a higher concentration of lower molecular weight biobased esters resulted in improved fluidity, but these compounds migrated more easily from the blends. Hence, 2,5‐furandicarboxylic acid derived from biomass has potential as a plasticizer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40938.     

Insights into biobased epoxidized fatty acid isobutyl esters from biodiesel: Preparation and application as plasticizer

Biodiesel was used to prepare epoxidized fatty acid isobutyl esters (Ep-FABEs) as a biobased plasticizer in this work. Transesterification of biodiesel with isobutanol catalyzed by tetrabutyl titanate was carried out in a gas-liquid tower reactor. The conversion achieved nearly 100% within 5 h under the reaction temperature, the mass ratio of catalyst to fatty acid methyl esters (FAMEs), and isobutanol to FAMEs total molar ratio of 180 ℃, 0.4 %(mass), and 5.4:1, respectively. In addition, kinetic model of the transesterification reaction was developed at 150–190 ℃. The calculated activation energy was 48.93 kJ·mol^-1. Then, the epoxidation of obtained fatty acid isobutyl esters (FABEs) was conducted in the presence of formic acid and hydrogen peroxide. The Ep-FABEs was further analyzed for its plasticizing effectiveness to replace dioctyl phthalate (DOP) and compared with conventional epoxy plasticizer epoxidized fatty acid methyl esters (Ep-FAMEs). The results indicated that the thermal stability and mechanical properties of PVC films with Ep-FABEs plasticizer were significantly improved compared with those plasticized with DOP. In addition, the extraction resistance and migration stability of Ep-FABEs were better than those of Ep-FAMEs. Overall, the prepared Ep-FABEs via structural modification of biodiesel proved to be a promising biobased plasticizer.     

Plasticization of poly(lactic acid) with oligomeric malonate esteramides: Dynamic mechanical and thermal film properties

Two oligomeric malonate esteramides and an oligomeric malonate ester were synthesized with the intention to plasticize poly(lactic acid), PLA. The synthesis was performed by reacting diethyl bishydroxymethyl malonate (DBM) with adipoyl dichloride and one of two diamines, that is, triethylene glycol diamine (TA) and polyoxypropylene glycol diamine (PA), or triethylene glycol (TEG), giving three platicizing agents denoted as DBMATA, DBMAPA, and DBMAT, respectively. The synthesis products were characterized by size exclusion chromatography and Fourier transform infrared spectroscopy, and blended with PLA at a concentration of 15 wt %. Dynamic mechanical analysis, differential scanning calorimetry, and tensile testing were used to investigate the physical properties of films from the resulting blends. All three plasticizers decreased the glass transition temperature of PLA, and the largest decrement was observed for PLA/DBMATA. Films of DBMATA and DBMAT showed enhanced flexibility in strain at break as compared to neat PLA. Subsequently, it was found that thermal annealing of the plasticized materials (4 h at 100°C) encouraged cold crystallization, inducing phase separation in the blends, and caused them to regain the brittleness of neat PLA. On the other hand, by aging (6 weeks) the blends at ambient conditions, cold crystallization could be avoided and the flexibility in the films maintained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 992–1002, 2005     

Ultrasonic welding of plasticized PLA films

Poly(lactic acid) (PLA) is a commercially available biobased material that has become an ideal material in packaging applications because of its low toxicity along with its environmentally friendly characteristics. Unfortunately, PLA is rigid and brittle. These characteristics impede its wide application. The flexibility of PLA can be improved by plasticization. In addition, welding polymer films is essential in the packaging production. Therefore, the weldability by means of ultrasonic welding of the neat and with polyethylene glycol plasticized PLA films was analyzed in this study. Moreover, the study examines the influence of the material composition on the processing window, that is, the range of welding parameters which could be used to weld films efficiently, and on the weld quality. This research showed that all examined films can be welded by ultrasonic welding. Furthermore, it was discovered that the addition of a plasticizer has a strong influence on the processing window and on the weld quality. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41351.     

Castor Epoxy Fatty Acid Alkyl Ester Estolides as Bioplasticizers for Poly(Vinyl Chloride)

Epoxy fatty acid alkyl ester estolides were synthesized from castor oil to be used as biobased plasticizers for poly(vinyl chloride) (PVC) as a safer replacement for phthalate plasticizers. Initially, castor oil was transesterified with methanol or n-butanol to quantitatively yield castor fatty acid alkyl esters. Acetylation of hydroxyl function with acetic anhydride led to the formation of estolide. The unsaturation was epoxidized, resulting in a bifunctional epoxy fatty acid alkyl ester estolide. The bioplasticizers were compounded with PVC and were evaluated for their functionality and compared with commercial phthalate plasticizer diisononyl phthalate (DINP) and nonphthalate 1,2-cyclohexanoic acid diisononyl ester (DINCH). The bioplasticizers showed excellent gelation, efficiency, and compatibility, as well as plastisol viscosity and thermal properties, comparable to or better than the plastisols prepared with commercial controls DINP and DINCH. The volatility of the methyl ester was inferior to the butyl ester. Both compounds showed low water resistance properties. Further evaluation of the butyl ester under tropical conditions of high temperature and humidity confirmed limited compatibility. This indicates that the castor epoxy fatty acid ester estolides would be better suited for applications that do not come in contact with water for prolonged periods, such as flooring, artificial leather, wiring, or wall coverings.     

Epoxidation of modified natural plasticizer obtained from rice fatty acids and application on polyvinylchloride films

In recent years, much research effort has been driven to develop alternative plasticizers for medical and commodity plastic materials. In this study, a modified natural plasticizer, synthesized by esterification of rice fatty acids, was modified by epoxidation with peroxy acid generated in situ. Two natural epoxidized plasticizers were obtained, using peracetic acid (NP‐Ac) and peroctanoic acid (NP‐Oc) as reagent. PVC films after addition of these natural epoxidized plasticizers presented fairly good incorporation and plasticizing performance, as demonstrated by results of mechanical properties, T_g values (as shown by DSC), optical microscopy, exudation, and migration tests, FTIR and X‐ray diffraction obtained for plasticized PVC films. NP‐Ac plasticizer presented enhanced plasticizing performance compared with NP‐Oc, probably due to a higher epoxidation degree obtained in the reaction with peracetic acid. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Poly(ε-caprolactone)-based additives: Plasticization efficacy and migration resistance

A family of poly(caprolactone) (PCL)-based oligomeric additives was evaluated as plasticizers for poly(vinyl chloride) (PVC). We found that the entire family of additives, which consist of a PCL core, diester linker, and alkyl chain cap, were effective plasticizers that improve migration resistance. The elongation at break and tensile strength of the blends made with the PCL-based additives were comparable to blends prepared with diisononyl phthalate (DINP), a plasticizer typically used industrially, and diheptyl succinate (DHPS), an alternative biodegradable plasticizer. Increasing concentration was found to decrease glass transition temperature (T_g) and increase elongation at break, confirming their role as functional plasticizers. We found that all of the PCL-based plasticizers exhibited significantly reduced leaching into hexanes compared to DINP and DHPS. The PCL-based plasticizers with shorter carbon chain lengths reduced leaching more than those with longer carbon chain lengths.