Equipment Best quality
Equipment Best quality is key Quality control and assurance for biopolymers B ioplastics have become indispensable nowadays, and the areas of application are constantly broadened. The level of the requirements has risen in equal measure. The industry of bioplastics demands for high quality biopolymers. Therefore appropriate analysing equipment for physical, chemical and rheological analysing are necessary to guarantee best properties for the fields of polymerisation, processing and application. Hence it is essential that the extrusion process is checked for function and documented, as the biopolymer film should be clear of contamination and gels. It is important to detect inhomogeneties as soon as possible so that the cause can be eliminated at an early stage of the process. The quality of granules, e.g. the size and shape, has an influence on the pneumatic conveyance and of course also on the material flow in the feeding process and extruder during high performance extrusion. For the further processing the frequency and size of gels and black specks in the film must be determined. These affect the optical appearance of the film and reduce the mechanical stability and ability for treatment, e.g. printing, laminating, etc. The surface quality is also an important quality control criterion when producing glossy and transparent films. Most bioplastics material contains additives for processing and preservation, the ingredients of which has to be analysed during quality inspection. OCS Optical Control Systems (Witten, Germany) offer online and off-line equipment that are very well known in the polymer & petrochemical industries worldwide. Therefore, many raw material manufacturers and extrusion & film processing companies trust in its ability to optimise the production process, its reliability and efficiency as well as the economical part impact. As one of the world’s leading manufacturer of optical testing systems for quality control, OCS supplies customised and complete solutions in the field of digital image processing, even the smallest defects in bioplastic products are detected, located and analysed in detail. The application for OCS systems range from laboratory use to complete integration into the production process. The solutions for the measurement of biopolymer properties in R&D environments The independence of the laboratory equipment in particular plays a decisive role in the development of biopolymers in R&D environments. These OCS solutions ensure absolute quality control and assurance. They control and influence the quality characteristics of biopolymers such as additives, matrixes, master batch compounds, or size and shape. Starting with OCS pellet scanner up to film analysis systems OCS will offer customised solutions for your research and development requirements. Benefits of production integrated on-line quality control and assurance Direct results, fast reaction and direct handling during the production process of biopplastics becomes more and more important. Therefore, not only the physical properties of bioplastics are essential, but furthermore the extrusion process has to be checked as well as the rheological behaviour and also molecular structure and chemical composition of the appropriate material are revealing quality indicators. The continuous control of biological stabilizers, lubricants, antiblocking agents, antioxidants and other additives has become an indispensable part of ongoing production processes. By using OCS equipment, the polymer process capability is highly increased, the quality growth, constancy and operation costs for the plant are significantly improved. When used as on-line system to optimise the process control, they shorten the response- and product change time, and provide quality assurance (QA). The OCS raw material analysers are modular concepts and applicable on OCS heavy duty industrial equipment for a fully automated testing line that fulfils all needs of a complete quality control & traceability as well as error detection. Furthermore the feeder for the smooth pellet transportation facilitates the connection between production lines & measurement systems and their transportation itself. Many customers have established a whole range of quality control predictions with a better precision and a faster analysis time. Typically the investment of one complete system is paid off in less than one year. With these OCS instruments all quality control requirements in modern bioplastic production and bioplastic conversion are fulfilled, offering tools for flawless history tracking of all critical parameters, for effective process control and for root cause analysis, creating a solid basis for process improvement. MT www.ocsgmbh.com OCS Cast film line with Measuring Extruder (ME) and Modular Film Analyser (MFA) for spectroscopical measurements (APLAIRS®), or gloss (OGM), haze & transmission (OHM) measurements. OCS Pellet Analysing System (PA66) measures various quality characteristics 34 bioplastics MAGAZINE [03/20] Vol. 15
From Science & Research Biodegradability of microcapsules I n many areas of life, petroleum-based plastics are being replaced with biobased and biodegradable plastics. This also applies to microcapsules, which are used, for example, to encapsulate fragrances in detergents or cosmetics. Although the bioplastics used for microcapsules are per se supposed to be produced from renewable raw materials and biodegradable, they often have to be chemically modified in order to improve materials’ properties, such as durability. A team of researchers at the Fraunhofer Institute for Applied Polymer Research IAP, Potsdam-Golm, Germany, is now testing to what extent these modified biobased microcapsules are still biodegradable. Fraunhofer IAP have been developing microcapsules for more than 25 years for a wide variety of applications - from encapsulated lubricants for moving plastic components such as gears or slide bearings, to fertilizers released in the soil over a long period of time and pigments that control the incidence of light in agricultural or greenhouse films. Cosmetic and hygienic products such as shower baths, shampoos or detergents also contain microcapsules made of modified natural substances such as gelatine. This biopolymer is often used as the wall material of microcapsules, which contain a fragrance and ensure that it is gradually released over a longer period of time. Natural substances are inherently biodegradable. They are undergoing a natural decomposition process in which organic matter is broken down by enzymes of microorganisms living in the soil. However, if natural substances are chemically modified, this can have a negative effect on their biodegradability. According to Kathrin Geßner, engineer in the Department of Microencapsulation and Polysaccharide Chemistry at the Fraunhofer IAP, there is very little data available in the scientific literature on the biodegradability of microcapsules, or particles in the size range from about one micrometer to several millimeters. Which is the reason they want to investigate various modified natural substances and establish a database with information on their biodegradability. The research would benefit not just microcapsules, but would also be interesting for a large number of other applications in which release of bioplastics into soil is possible. In order to be able to make a statement about biodegradability, the researchers carry out a manometric respiration test in accordance with OECD 301 F based on DIN EN ISO 14851. The researchers obtain the oxygen demand of the sample directly as a measured value. If the sum formula is known, the theoretical oxygen demand and finally the biochemical oxygen demand, or BOD, can be calculated. If a degradation value of 60 % of the theoretical oxygen demand is achieved for the substance under investigation, it is considered to be biodegradable according to OECD 301 F. “Among other things, we are developing microcapsule materials that biodegrade in an aqueous medium at 20 °C within 28 days. We get the microorganisms fresh from the sewage plant for each measurement,” says Geßner. Another test method is available in the biopolymer processing pilot plant at the Fraunhofer IAP’s Schwarzheide site, in which the oxygen consumed is not only measured but also can be replaced. In this way, aerobic degradation conditions can always be maintained even with high oxygen consumption. In addition, the formation of carbon dioxide, which is produced during sample degradation, can be measured too. With the two measuring systems the samples can be examined in different test media. Thus, the biodegradability in freshwater, sea water or soil can be simulated and diverse information can be collected for the database. In their series of investigations, the researchers determine the biodegradability of commercially available biopolymers before and after their modification. Chemical crosslinking of biopolymers is often used for the production of microcapsules. “By the end of 2020, we want to examine all biopolymers routinely used in our company and their modifications. Initial investigations with gelatine and gum arabic suggest that many of the modifications routinely used in microencapsulation processes have only a minor effect on the biodegradability of polymers. The situation seems to be different, however, with cellulose acetate: Depending on the type of modification, the biodegradability might even be completely lost,” explains Geßner. Other biopolymers that the team of researchers will examine are alginate, carrageenan and polylactide. In addition to microcapsules and particles, the biodegradability of other materials and products developed at the Fraunhofer IAP is also being investigated, for example blends and compounds made from commercially available or in-house developed modified bioplastics such as PLA, PBS, PBSA, PBAT and starch- and cellulose-based plastics. AT www.iap.fraunhofer.de With the help of a test system, the oxygen demand during biodegradation in fresh water, seawater or soil can be determined for a wide variety of samples. bioplastics MAGAZINE [03/20] Vol. 15 35
