Extrusion Blow Research Articles

Circular Economy Assessment in Recycling of LLDPE Bags According to European Resolution, Thermal and Structural Characterization.

According to the Circular Economy Package promoted by the European directive, plastic bags companies must use in their formulations a percentage of polyethylene waste (industrial and/or domestic) greater than 70%. Following that regulation requires an understanding of its consequences in the final product from an industrial point of view. This manuscript analyzes the thermal and morphological changes related to the tear resistance of linear-low density polyethylene (LLDPE) samples from industrial waste generated by the company Sphere Spain subjected to the degradation produced by the recycling cycles. The process is analogue to the industrial, starts from samples in pellets then a film by blow extrusion is obtained (odd steps) and posteriorly this film is recycled to pellets again (even steps). The results obtained show that the LLDPE samples develop two crystalline structures (CS1 and CS2) which evolve differently through the recycling cycles with a tendency to decrease in crystallinity due to degradation that is not the same for the process of obtaining film or recycling to pellet. The molecules with a more linear structure and a longer chain break and branch. The more branched structure increases and tends to crosslinking. This leads to a decrease in tear strength in the longitudinal direction, which is not so evident in the transversal direction. The samples could admit four recycling cycles with and acceptable tear resistance. The longitudinal tear strength value decreases by 40% for each film and 20% in the case of tearing in the transverse direction. The results obtained in this research work show that the regulations included in the cited circular economy package can be applied in the manufacture of consumer bags, helping also to reduce the dependence of manufacturers on fluctuations in delivery by collapses in shipping.

Starch/PBAT blown antimicrobial films based on the synergistic effects of two commercial antimicrobial peptides

In this study, starch/PBAT antimicrobial film, based on the synergistic effects of two commercial antimicrobial peptides, was fabricated by blown extrusion. The blends with nisin exhibited higher storage modulus and complex viscosity than those with ε-polylysine hydrochloride (ε-PL) alone. ATR-FTIR spectra revealed that new intermolecular hydrogen bonds were formed among starch, nisin, and ε-PL. XRD results indicated that antimicrobial peptides facilitated the destruction of the original crystalline structure of starch. Combination of ε-PL and nisin enhanced tensile strength, flexibility, moisture permeability, and oxygen barrier property of the films with more homogeneous morphology. SP-PN1/2 film (1% ε-PL + 2% nisin) exhibited over 90% inhibition rates against Staphylococcus aureus and Escherichia coli, and prolonged the shelf life of fresh peaches. The antimicrobial film with nisin and ε-PL showed high safety, cost-effectiveness, consumer acceptability, and thus it had a good application prospect in the food packaging field.

Properties and Degradability of Poly(Butylene Adipate-Co-Terephthalate)/Calcium Carbonate Films Modified by Polyethylene Glycol.

Poly(butylene adipate-co-terephthalate) (PBAT) is a biodegradable polymer synthesized from petrochemical resources. PBAT has an exceptionally high elongation at break values which makes it one of the most promising substitutes for LDPE packaging films. However, the applicability of PBAT films is still limited by low strength and high production costs. In this work, we used polyethylene glycol 600 (PEG-600) as a coating agent to modify the surface of calcium carbonate and improve compatibility with the polymer matrix. A series of PBAT/CaCO3 composite films having different CaCO3 particle size and content of coating agent was prepared using extrusion blow molding. The effect of particle size of CaCO3 filler and the content of a coating agent on the mechanical and rheological properties of composite films have been studied. The biodegradation properties have been tested by burying the samples in soil or keeping them in artificial seawater for 90 days. It was shown that the addition of PEG-600 improves compatibility between the matrix and CaCO3 filler as polar –OH groups of PEG have a high affinity toward the polar surface of CaCO3. Moreover, the hydrophilicity of PEG-600 increased the diffusivity of water molecules and facilitated PBAT degradation. This work provides experimental data and theoretical guidance that support the development of high-performance PBAT/calcium carbonate films for the single use packaging industry.

Effect of thymol on physical properties, antimicrobial properties and fresh-keeping application of cherry tomato of starch/PBAT extrusion blowing films

In order to explore the effects of thymol on the antimicrobial activity, structure, physical properties and fresh-keeping application of starch/PBAT composite films, different contents of thymol (0, 1%, 3% and 5%) were used to prepare antimicrobial composite films by extrusion blow molding. The results indicated that tourier transform infrared spectroscopy showed there was intermolecular hydrogen bonding force among starch/PBAT and thymol. The inhibition effect on Botrytis cinerea and the preservation effect of cherry tomato of the composite film were significantly improved, the hardness and nutritional characteristics of cherry tomato were maintained, and the fruit decay rate was reduced. The addition of thymol increased the water vapor permeability of the starch based composite films, but reduced the interaction between the composite film and water. Although thymol reduced the mechanical properties of the composite film, high concentration of thymol further improved the mechanical properties. In conclusion, the high concentration of thymol improved the comprehensive properties of starch composite film, and proved the application prospect of the film as active food packaging material.

Closed-loop thickness control and sensor placement in extrusion blow moulding

Extrusion blow moulding (EBM) is a polymer forming technique used to manufacture hollow plastic parts, such as fuel tanks. In this work, the feasibility of using closed-loop control in EBM is explored to compensate for machine drift and disturbances. A control system is proposed to regulate the extrusion process in EBM. The extrusion controller aims to increase process consistency by minimizing part thickness deviations. The thickness of the extrudate is measured during the extrusion cycle and any deviation from the desired thickness profile is compensated by changing the die gap in real time. The controller, which offers flexibility in thickness sensor placement, features a Smith predictor configuration embedding an H∞ controller. It compensates for the input-dependent polymer transport delay, the nonlinear steady-state swell, and nonminimum phase necking effects affecting the extrudate. This extrusion control technique may help reduce the production rate of off-specification parts and improve product quality.

Closed-loop thickness control and sensor placement in extrusion blow moulding

Closed-loop thickness control and sensor placement in extrusion blow moulding

Low temperature extrusion blown ε-polylysine hydrochloride-loaded starch/gelatin edible antimicrobial films

Edible antimicrobial films made from starch/gelatin (S/G) incorporated with different ε-polylysine hydrochloride (ε-PL) contents were developed by low-temperature extrusion blowing process. ε-PL addition reduced the complex viscosity and storage modulus of blends, while promoted the formation of hydrogen bonding among film components. The control film had an A-type crystalline structure, while increasing the ε-PL content promoted its transformation to B-shaped structure. Without ε-PL and under the processing temperature used, the starch granules were not sufficiently gelatinized. However, ε-PL addition significantly enhanced the gelatinization degree. Increasing ε-PL content in S/G films increased film flexibility, water contact angle value, swelling degree, antimicrobial effect, and storage period of fresh bread, but decreased water vapor permeability and tensile strength. S/G film with 4 wt% ε-PL had the highest water contact angle (94°) and elongation at break (149%). This research demonstrates the plasticizing effects of ε-PL and potential of S/G films containing ε-PL for food preservation/packaging.

Overlapping grid spectral collocation approach for electrical MHD bioconvection Darcy–Forchheimer flow of a Carreau–Yasuda nanoliquid over a periodically accelerating surface

AbstractThe focus of this study is on computational grid‐manipulation to enhance the accuracy, convergence, and computational efficiency of the multidomain bivariate spectral local linearization method (MD‐BSLLM). The improved method is used in the scrutiny of Darcy–Forchheimer bioconvection flow of Carreau–Yasuda nanofluid induced by an oscillatory moving surface with cross‐diffusion, activation energy with binary chemical reactive species, combined electrical and magnetohydrodynamic field effects. The proposed method is utilized in solving the nondimensional form of the flow equations. Sensitivity and error analyses are provided to aid an understanding of the efficiency, stability, convergence rate, and accuracy of the iterative scheme. The impact of different parameter values on fluid properties and transport phenomena is discussed. Numerical simulation has indicated that the overlapping grid MD‐BSLLM is computational efficacious, and produces stable and sufficiently accurate results using a few collocation nodes in each respective subinterval and the entire computational domain. Other findings include the fact that fluid properties are enhanced with injection while flow characteristics are improved with suction. Using the Darcy–Forchheimer model in the flow analysis improves the temperature of the nanofluid. The imposition of electric field augments nanofluid velocity, the amplitude of skin friction coefficient, rates of mass, and motile microorganisms transfer while reducing the rate of heat transfer. The considered flow analysis can contribute towards engineering solicitations in paper production, polymer solution, metal extrusion, and glass blowing.

Recycled LDPE/PETG blends and HDPE/PETG blends: mechanical, thermal, and rheological properties

The recycled low density polyethylene (LDPE), recycled high density polyethylene (HDPE) and recycled polyethylene terephthalate G copolyester (PETG) as post-processed plastic wastes from extrusion blow molding process were modified with blending process to improve the properties of those plastic wastes and decrease the amount of plastic wastes in the plastic processing plants. The recycled PETG was blended with recycled LDPE and recycled HDPE in various concentration from 0 wt% to 100 wt% in increments of 10 wt% as referred to LDPE/PETG blends and HDPE/PETG blends respectively prepared by co-twin screw extruder. The addition of PETG in the blending of LDPE and HDPE improved the mechanical properties and MFI of those polymer blends but decreased thermal stability, storage modulus, loss modulus and complex viscosity as compared to those of neat LDPE and neat HDPE. LDPE/PETG blends illustrated better impact properties and flexibility than those of HDPE/PETG blends.

STUDY OF DEFECT ON 180 ML HDPE BOTTLES YOGURT PRODUCTS WITH SMC B11 EXTRUSION BLOW MACHINE AT PT X

The type of plastic packaging that is popular in the community is bottle packaging. The plastic material that is generally used to make plastic bottles is High Density Polyethylene (HDPE). The plastic bottle industry in Indonesia usually uses a blow molding process in its production process, where the blow molding process consists of injection blow molding, extrusion blow molding and stretch blow molding. The SMC B11 machine is one of the extrusion blow molding machines used to produce plastic bottle packaging. In producing workpieces, this machine still produces several products that are not in accordance with company standards, including in terms of production cycle times and product defects. Defects or defects that are often encountered include the appearance of spots, bent parison which causes the bottle to bend (the bottle body is thin one side) and blow pin which causes the thread to not fit.Keywords— Bottle, Plastic, Defect, Extrussion Blow Molding

Effect of lipids with different physical state on the physicochemical properties of starch/gelatin edible films prepared by extrusion blowing

The effects of various physical state lipids (rapeseed oil (RO), shortening (ST), beeswax (BW)), on the physicochemical properties of starch (S) (hydroxypropyl distarch phosphate (HP), oxidized hydroxypropyl starch (OS))/gelatin (G) blown films were studied. S/G-lipid blends showed decreased storage modulus and complex viscosity. The formation of hydrogen bonds was inhibited by the ST and BW, but facilitated by the RO. Compared with BW and ST, RO was more effective to promote the melted and fractured of starch. Lipids addition promoted the compatibility of starch and gelatin. The presence of the lipids significantly improved the surface hydrophobicity, mechanical, water vapor barrier and water resistance properties of S/G films. S/G-RO films exhibited the strongest surface hydrophobicity and tensile strength, while HP/G-BW film showed the strongest water resistance and water vapor barrier properties. These results revealed that the appropriate lipids could be used to produce S/G-lipid films with desirable physicochemical properties.

Corotating twin‐screw extrusion of poly(lactic acid)PLA/poly(butylene succinate)PBS/ micro‐lamellar talc blends for extrusion blow molding of biobased bottles for alcoholic beverages

AbstractExtrusion blow molding is a well‐established technology for the manufacture of fossil‐based plastic bottles. The process is, however, still little used for the manufacture of bottles with a low environmental footprint, especially those based on bioplastic from renewable sources. In this context, the objective of this work is precisely the study and experimental design of poly(lactic acid) PLA/poly(butylene succinate) PBS/micro‐lamellar talc compounds for the manufacturing of bioplastic bottles, basically for wine packaging. In particular, the design was carried out to ensure, primarily, an adequate processability of the bioplastic material in the blowing process. Second, the compound was loaded with different micro‐lamellar talc content so as to achieve protection from the environmental factors, which is of paramount importance to ensure a long shelf‐life to wine. The bio‐derived polyester resins are very complex to transform, as they are subject to thermo‐hydrolytic degradation phenomena during the processing of the polymer melt. Processability is further limited in the presence of high micro‐lamellar talc content that increases the melt viscosity, thus making the material even more difficult to shape by extrusion blow molding. The experimental analysis involved the use of a co‐rotating twin‐screw extruder for the manufacture of the bioplastic compounds. The compounds were first subjected to thermo‐rheological and physical characterization tests. Second, it was tested in the extrusion blow molding process. The experimental results have shown that blends based on bio‐derived polyester resins can be adequately processed by extrusion blow molding, showing extremely stable rheological behavior both during the extrusion phase of the parison and the subsequent blowing process of the parison itself. These blends have, therefore, an interesting potential to be used as an alternative with a low environmental footprint to oil‐based plastics in the production of wine bottles.

Development and characterization of starch films prepared by extrusion blowing: The synergistic plasticizing effect of water and glycerol

Herein, we have investigated the synergistic plasticizing effect of water (W) and glycerol (G) on the physicochemical and structural properties of starch-based films prepared by extrusion blowing. Fourier transform infrared spectroscopy (FT-IR) revealed that glycerol could act as a typical plasticizer in the presence of sufficient amounts of water (approximately 15%). All the films exhibited a B + V-type crystalline structure by X-ray diffraction (XRD). We hypothesize that there were two stages for the effect of plasticizer on the mechanical properties of the composite film. The crystallinity, thermal stability, and water vapor permeability (WVP) of the film initially decreased and then increased with increasing water content from 0 to 20%. The opposite trends were observed for surface smoothness and surface hydrophobicity. Moreover, the addition of 15% G-15% W co-plasticizers was optimal for film blowing, which can substantially reduce the cost of producing starch-based films.

Characterization and application of starch/polyester packaging produced by blown extrusion

All over the world, most of the food packaging is mainly petroleum-based. These packagings become worrying plastic waste due to use and disposal that includes accumulation in natural habitats. Thermoplastic starch/poly(butylene adipate-co-terephthalate has been investigated in the production of biodegradable films. Also over time, new forms of food packaging have emerged, such as active and intelligent packaging. Active packaging offers a solution to food quality. This research aimed to develop a biodegradable active packaging by blown extrusion for fresh bananas (Musa sp Cavendish cv. Nanicão) to increase the shelf life of the fruit. In this study, modified zeolite was used as ethylene scavenger and bromothymol blue and methyl red as ripeness indicators. Four treatments were processed by blown extrusion: perforated and non-perforated control films, perforated and non-perforated films containing zeolite (1.5 %), and the last treatment as control: non-packed banana. The films were characterized for water sorption isotherms, scanning electron microscopy, water vapor permeability, and mechanical properties. Bananas were stored for 7 days at 25 °C. Films with zeolite preserved the banana texture during storage time but were more rigid and less flexible. Further research is needed to determine variants that could make this alternative viable.

Preparation and evaluation of starch-based extrusion-blown nanocomposite films incorporated with nano-ZnO and nano-SiO2

The effects of nano-ZnO and nano-SiO2 nanoparticles on the properties of starch-based films prepared by extrusion blowing were investigated in this study. New hydrogen bonds between hydroxypropyl starch (HS) and nanoparticles during the extrusion process were formed as shown by Fourier transform infrared spectroscopy (FTIR). The diffraction patterns of nanocomposite films reinforced with nano-ZnO were similar to those of nano-ZnO, except that the peak intensity decreased, whereas, the addition of SiO2 nanoparticles decreased the intensity of the main characteristic peaks, regardless of the HS and nano-ZnO reinforced films. The thermal stability, tensile strength, moisture barrier property, and surface hydrophobicity of nanocomposite films were improved with the incorporation of nano-ZnO and nano-SiO2, the finding that could be attributed to a strong interplay between nano-ZnO, nano-SiO2, and the starch matrix during the extrusion film blowing process. Similarly, the nano-ZnO/nano-SiO2 composite-reinforced films showed smooth, flat, and uniform appearances by scanning electron microscopy (SEM) and atomic force microscope (AFM) tests. In sum, Nano-ZnO and nano-SiO2 nanoparticles can be used as composite reinforcing agents for preparation of starch-based films through extrusion blowing.

Design, manufacturing and preliminary assessment of the suitability of bioplastic bottles for wine packaging

The aim of this study is to evaluate the suitability of bioplastic bottles for wine packaging. The wine is largely packaged in glass bottles, although alternative solutions such as laminate, plastic and bag-in-box packaging are decidedly widespread on the market by virtue of their ease of use and low cost, especially for the so-called entry-level products. However, packaging involving the partial or exclusive use of plastic is the subject of discussion in the scientific community, by virtue of the persistence of plastic materials in the environment at the end of the product life cycle. A solution that could reconcile the practicality and low cost of plastic packaging with a reduced environmental footprint is the replacement of fossil-based plastics with compostable bioplastics. The latter biodegrade if properly treated at the end of their life, limiting the environmental footprint of the packaging. Bioplastics are, however, more complex to process than conventional plastics, also presenting a higher cost. The objective of this study is therefore the manufacture of prototype bottles in bioplastic for the packaging of wine by means of an extrusion blow molding process, as well as the evaluation of the main thermo-mechanical and physical properties of the same.

Production of Wheat Flour/PBAT Active Films Incorporated with Oregano Oil Microparticles and Its Application in Fresh Pastry Conservation

This study aimed to produce wheat flour and poly (butylene co-terephthalate adipate) films with the addition of free and microencapsulated oregano essential oil by blown extrusion and to evaluate its applicability as an active packaging in the preservation of the Brazilian fresh pastry, known as Pastel. The oregano essential oil microparticles were produced by spray drying and characterized in terms of morphology, encapsulation efficiency, and mean diameter. In the films, the physical, antioxidant, and diffusion kinetics of oregano essential oil were determined. Films with microencapsulated oregano essential oil showed lower tensile strength and Young’s modulus and higher elongation, solubility, antioxidant capacity, and diffusion coefficient when compared to the control and free oregano oil films. During 28 days of refrigerated storage, fresh pastry packaged with film with oregano essential oil microparticles presented a lower count of molds and yeasts, compared to pastries packed with control and free oregano oil films. The microencapsulation protected oregano essential oil from extrusion condition shearing and temperature damages during film production, allowing the development of biodegradable active films for application in foods where contamination by molds and yeasts is predominant.

Effects of Nopal Mucilage (Opuntia ficus-indica) as Plasticizer in the Fabrication of Laminated and Tubular Films of Extruded Acetylated Starches

Normal and acetylated rice and waxy maize starches with a blend of nopal mucilage (Opuntia ficus-indica) and glycerol were used for the preparation of laminated and tubular films by extrusion and blown extrusion, respectively. The composition of the formulation was 70% starch (normal or acetylated), 20% glycerol, and 10% nopal mucilage ( w / w ). The degrees of substitution (DS) for acetylated rice starch (0.94) and waxy maize starch (0.76) present high potential for use as a polymeric matrix in packing materials. The use of nopal mucilage can improve the processability of extruded and tubular films by favoring the increase of some mechanical and functional properties. The films elaborated with nopal mucilage and glycerol present a homogeneous relief without breaking, adhesiveness, and contraction once formed. The elongation values of acetylated waxy maize starch films (33%) were higher than those of rice acetylated films (17%), while the blown films presented a 30% decrease in tensile strength, compared to the laminated films. Acetylation generated more hydrophobic material for the rice starch sample, which can be evidenced by a decreased solubility of the laminated films. Films of both sources of acetylated starch showed a significant decrease in water vapor permeability and showed a plasticized starch disposition-type layer without unmelted starch granules.

Preparation of low‐density polyethylene‐ and poly (lactide)/poly (butylene adipate‐co‐terephthalate)‐based antibacterial films integrated with elemental sulfur and sulfur nanoparticles

Antibacterial low‐density polyethylene (LDPE)‐ and poly (lactide)/poly (butylene adipate‐co‐terephthalate) (PLA/PBAT)‐based films incorporated with elemental sulfur (ES) and sulfur nanoparticles (SNPs) were prepared using a blow extrusion method for food packaging applications. Flexible and free‐standing films were manufactured using an industrial processing method without any modification. The films were characterized using ultraviolet (UV)–visible spectroscopy, field emission scanning electron microscope (FESEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). Also, film properties include optical, mechanical, surface hydrophobicity, thermal stability and antibacterial activity. The addition of ES and SNP significantly reduced the light transmittance (both UV and visible light) of LDPE‐ and PLA/PBAT‐based films and slightly reduced mechanical properties but did not affect thermal stability. The ES‐ and SNP‐added films showed apparent antibacterial activity against the Gram‐positive foodborne pathogenic bacteria (Listeria monocytogenes). In general, SNP showed superior film properties and antibacterial properties compared to ES, but ES also showed comparable properties as SNP. Antibacterial LDPE‐ and PLA/PBAT‐based films can be produced on an industrial scale and used in the packaging of refrigerated foods susceptible to L. monocytogenes contamination.

Active Biodegradable Packaging for Foods Containing Baccharis dracunculifolia Leaf as Natural Antioxidant

Baccharis dracunculifolia DC (Asteraceae) is a Brazilian native plant that has excellent antioxidant properties. This work aimed to develop an active biodegradable packaging for food using B. dracunculifolia leaf powder as a natural antioxidant. Biodegradable films were produced by blown extrusion with cassava starch, poly (butylene adipate-co-terephthalate), glycerol, and leaf powder of B. dracunculifolia (1.25, 2.5, and 5.0 wt.%), and the films were tested as active packaging for different food simulants. The B. dracunculifolia improved the tensile strength and elongation of the films. The films’ antioxidant activities were proportional to the B. dracunculifolia content with the DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), and TPC (Total Phenolic Compounds), reaching 3.95 μmol of Trolox g film−1, 10.60 μmol of TEAC g film−1, and 0.97 mg GAE g film−1, respectively. B. dracunculifolia is an excellent font of natural antioxidants, and it can be used in active biodegradable packaging for food products.