Evaluation of the Properties of PHB Composite Filled with Kaolin Particles for 3D Printing Applications Using the Design of Experiment

In the presented work, poly(3-hydroxybutyrate)-PHB-based composites for 3D printing as bio-sourced and biodegradable alternatives to synthetic plastics are characterized. The PHB matrix was modified by polylactide (PLA) and plasticized by tributyl citrate. Kaolin particles were used as a filler. The mathematical method “Design of Experiment” (DoE) was used to create a matrix of samples for further evaluation. Firstly, the optimal printing temperature of the first and upper layers was determined. Secondly, the 3D printed samples were tested with regards to the warping during the 3D printing. Testing specimens were prepared using the determined optimal printing conditions to measure the tensile properties, impact strength, and heat deflection temperature (HDT) of the samples. The results describe the effect of adding individual components (PHB, PLA, plasticizer, and filler) in the prepared composite sample on the resulting material properties. Two composite samples were prepared based on the theoretical results of DoE (one with the maximum printability and one with the maximum HDT) to compare them with the real data measured. The tests of these two composite samples showed 25% lower warping and 8.9% higher HDT than was expected by the theory

Utilization of Waste Lignin and Hydrolysate From Chromium Tanned Waste in Blends of Hot-Melt Extruded PVA-Starch

The demand for biodegradable plastic material is increasing worldwide. However, the cost remains high in comparison with common forms of plastic. Requirements comprise low cost, good UV-stability and mechanical properties, as well as solubility and water uptake lead to the preparation of multi-component polymer blends based on polyvinyl alcohol and starch in combination with waste products that are hard to utilize—waste lignin and hydrolysate extracted from chromium tanned waste. Surprisingly the addition of such waste products into PVA gives rise to blends with better biodegradability than commercial PVA in an aquatic aerobic environment with non-adapted activated sludge. These blends also exhibited greater solubility in the water and UV stability than commercial PVA. Tests on the processing properties of the blends (melt flow index, tensile strength and elongation at break of the films) as well as their mechanical properties showed that materials based on these blends might be applied in agriculture (for example as the systems for controlled-release pesticide or fertilizer) and, somewhat, in the packaging sector. © 2017, Springer Science+Business Media, LLC.Tomas Bata University in Zlin [IGA/FT/2016/012]; Ministry of Education, Youth, and Sports of the Czech Republic within the NPU I program [LO1504

Application of Protein Hydrolysate from Chrome Shavings for Polyvinyl Alcohol-based Biodegradable Material

In this work, the additive applied for this purpose was protein hydrolysate producedd by enzymatic hydrolysis of chrometanned shavings. It was used for modifying polyvinyl alcohol which had been processed into water-soluble films often employed in agriculture. This material, after being deposited in soil, undergoes biological degradation (first of all anaerobic) which is supported to a large extent by the addition of protein hydrolysate in particular. For this reason, anaerobic biodegradability tests were performed (volumetric test determining methanogenic activity) and the corresponding percentage of degradation was determined based on a balance of produced biogas and inorganic carbon in the aqueous phase. Polyvinyl alcohol is relatively poorly degradable under aerobic conditions while protein hydrolysate, on the contrary, undergoes biodegradation at a fairly fast rate. From a comparison between the attained degradation degree of blow-extruded film and that of mechanically prepared compounds it follows that the limiting factor of degradability, apart from added protein hydrolysate, is also a chemical reaction between polyvinyl alcohol and hydrolysate taking place during the heat processing of film. It was confirmed that protein hydrolysate from chrome shavings markedly increases biodegradation of material (depending on its content in the plastic matrix), reduces the final cost of product and, last but not least, to some extent also exerts a positive influence on mechanical properties of the film

Biodegradability of water soluble plastic films based on polyvinyl alcohol in aerobic water environment. The application of respirometric and Zahn-Wellens tests.

Biodegradation of plastic films based on polyvinyl alcohol and protein hydrolysate under aerobic condition was assessed by means of respirometric test (bod measurements) and/or Zahn-Wellens test. The tests were provided in water envirofnment after inoculation by activated sludge drawn-up from waste water treatment plant. 13 mixed film blends were tested it was found that biodegradation of these blends was practicaly non-independečntable on their compoisiton

Assessing biodegradability of plastics based on poly(vinyl alcohol) and protein wastes

Research was conducted into biodegradability of mixeds polymer films based on poly(vinyl alcohol), protein hydrolyzate (collagen hydrolyzate from wastes after chrome tanning) and sglycerol in an aqueous aerobic environment. Evaluation of biodegradation was based on carbon dioxide produced in the gas phase. Pure PVAL was degraded by a current mixed culture for water-treatment (unadapted) only after an approx. 10-day lag phaseduring breakdown of mixed film the protein component and glycerol were broken down first and PVAL degradation occurred in the second stage. Biodegradation could be well described by 1st-order formal chemical kinetics. Repeated degradation by an adapted culture proceeded in a single stage with considerably shorter lag phase (< 30 h) at a simultaneously approx. 1.5-fold greater breakdown rate (rate constants). During degradation of substrates containing PVAL, microbiological tests proved an approx. 100-fold increase in numbers of PVAL-degrading bacteria. Added protein hydrolyzate + glycerol in PVAL contributed to increasing biodegradability more than followed from proportional representation of individual components

Poly(vinyl alcohol)-collagen hydrolysate thermoplastic blends: I. Experimental design optimisation and biodegradation ...

Hybrid blends based on poly(vinyl alcohol) (PVA) and collagen hydrolysate (CH), an abundant, added value waste product of the leather industry, have been processed by melt blow extrusion to environmentally degradable films. Optimisation of the blend compositions was performed in respect of mechanical properties of the films. The experimental design method (DOE) was used for the understanding of the structure-property relationships in the hybrid blends using glycerol as a plasticiser. Parameters were selected from torwue measurements, melt flow index, thermogravimetric analysis, as well as tensile strength and elongation at break of the plasticised blends. The use of the DOE method offers the possibility of identifying a range of blend compositions suitable to yield products with valuable mechanical and thermal properties. Biodegradation experiments performed under anaerobic conditions evidenced a positive effect of collagen hydrolysate on the mineralization rate of PVA/CH blends

Poly(vinyl alcohol)-collagen hydrolysate thermoplastic blends: II. Water penetration and biodegradability of ....

Water solubility of polyvinyl alcohol (PVA) is related to degree of hydrolysis, molecular weight and modification during blending in the presence of other processing additives. In the present paper the effect of collagen hydrolysate (CH) and glycerol on PVA water sensitivity has been investigated. CH content affects water penetration into the prepared blown films, affecting therefore their solubility. An increasing content of CH in PVA based blends shortens the time to the first disruption of the film after immersing in water, restraining the negative effect of glycerol on solubility. Pure PVA film presented limited biodegradation at low temperature (5 oC). The CH addition in the blend significantly increases biodegradation rate at that temperature. PVA/CH blends properties are of practical relevance for applications as hospital laundry bags and containers of water-soluble substances, such as chemical agents for treatment of waste and potable water, fertilizers, washing agents, sanitary products, etc

Effect of Selected Commercial Plasticizers on Mechanical, Thermal, and Morphological Properties of Poly(3-hydroxybutyrate)/ Poly(lactic acid)/Plasticizer Biodegradable Blends for Three-Dimensional (3D) Print

This paper explores the influence of selected commercial plasticizers structure, which are based on esters of citric acid, on mechanical and thermal properties of Poly(3-hydroxybutyrate)/Poly(lactic acid)/Plasticizer biodegradable blends. These plasticizers were first tested with respect to their miscibility with Poly(3-hydroxybutyrate)/Poly(lactic acid) (PHB/PLA) blends using a kneading machine. PHB/PLA/plasticizer blends in the weight ratio (wt %) of 60/25/15 were then prepared by single screw and corotating meshing twin screw extruders in the form of filament for further three-dimensional (3D) printing. Mechanical, thermal properties, and shape stability (warping effect) of 3D printed products can be improved just by the addition of appropriate plasticizer to polymeric blend. The goal was to create new types of eco-friendly PHB/PLA/plasticizers blends and to highly improve the poor mechanical properties of neat PHB/PLA blends (with majority of PHB) by adding appropriate plasticizer. Mechanical properties of plasticized blends were then determined by the tensile test of 3D printed test samples (dogbones), as well as filaments. Measured elongation at break rapidly enhanced from 21% for neat non-plasticized PHB/PLA blends (reference) to 328% for best plasticized blends in the form of filament, and from 5% (reference) to 187% for plasticized blends in the form of printed dogbones. The plasticizing effect on blends was confirmed by Modulated Differential Scanning Calorimetry. The study of morphology was performed by the Scanning Electron Microscopy. Significant problem of plasticized blends used to be also plasticizer migration, therefore the diffusion of plasticizers from the blends after 15 days of exposition to 110 degrees C in the drying oven was investigated as their measured weight loss. Almost all of the used plasticizers showed meaningful positive softening effects, but the diffusion of plasticizers at 110 degrees C exposition was quite extensive. The determination of the degree of disintegration of selected plasticized blend when exposed to a laboratory-scale composting environment was executed to roughly check the biodegradability