Polylactic acid processing solution

From the birth of the first synthetic plastic in 1907, nowadays all kinds of plastics have entered every corner of people's lives and become a part of human society. The plastics industry has come a long way in a century. However, 100 years later, when we enjoy the convenient and comfortable life that plastic brings, we have to face all kinds of problems caused by it. The first thing to suffer is environmental pollution. The chemical composition of traditional plastics is stable and it is difficult to degrade and disappear. . In response to this problem, various countries have successively issued regulations restricting the use of plastic products, such as China's notice on restricting production and sales of plastic shopping bags on June 1 this year. At the same time, the industrial community is also constantly striving to find alternatives to traditional plastics. Among them, polylactic acid (PLA) has received the most extensive attention and application due to its long research time and mature technology. It is expected to replace plastics in packaging and engineering plastics. Traditional plastic. Unlike traditional petroleum-based plastics, polylactic acid is produced by the polymerization of lactic acid derived from vegetable starch, which is a renewable resource. At the same time, polylactic acid has good biodegradability, and plastic products made of it can be automatically degraded into water and carbon dioxide within 6 months to 12 months after being disposed in the soil after being discarded. The harm to the environment is far less than traditional plastic.
Polylactic acid also has good processing properties and can be applied to traditional extrusion, injection molding, blow molding and other processing methods. However, due to the unique molecular structure of polylactic acid, its viscosity will rapidly decrease with the increase of temperature during processing. At the same time, the melt strength will decrease, the melt will break and relax, and the yield will decrease. These problems are particularly prominent in processes that require melt strength, such as blow molding and foaming. Therefore, how to increase the melt strength of polylactic acid and improve its processing performance to expand its application prospect has become a new problem before the industry.
Rohm and Haas (Rohm and Haas) is a world-class chemical supplier. At the same time, it is also a highly socially responsible company. It has always dedicated itself to the application and promotion of biodegradable materials and the production of world-famous degradable materials. Businessmen also have extensive and close contacts. Last year, Rohm and Haas partnered with the world's largest polylactic acid producer (Naturework) to launch a PARALOIDTM BPM-500 specifically for the toughening and modification of polylactic acid transparent application systems. Today, Rohm and Haas Company has provided PARAMOIDTM BPMS-255,265, an improved solution for the processing performance of polylactic acid, thanks to its strong technical foundation and rich experience in the field of plastic processing aids.
PARALOIDTM BPMS is a new concept of processing aids. Its specially designed composition and molecular structure can effectively interact with polylactic acid molecules during processing to form a uniform physical network structure (to avoid the formation of gels) to increase melting. Body strength. Once the melt strength is increased, the melt fracture can be effectively prevented during the processing, making the process more stable, thereby increasing the yield. At the same time, the quality of the product can also be improved to some extent, such as reducing the thickness of the polylactic acid film under the blow molding process, and the like.
The PARALOIDTM BPMS series processing aids introduced this time have two grades, BPMS-255 and BPMS-265. The elongational viscosity of BPMS and polylactic acid system in the molten state can be obtained by an extensional viscosity fixture, which is an important physical parameter and directly reflects the melt strength of the polymer system. In the experiment, it can be found that as long as 2% of BPMS can significantly improve the melt strength of the polylactic acid system, and at the addition amount of 5%, the melt strength of the entire system can be improved to an ideal level. At the same time, the increase in the melt viscosity of the system by BPMS is not significant and will not introduce new problems in the process. It can be seen from the experimental results (Figure 1) that in both brands, the same amount of 5%, BPMS-255 can provide moderate melt strength, while BPMS-265 provides higher melt strength.
At the same time, the BPMS series also takes into account the requirements for material transparency for certain applications. The molecular composition of the BPMS series allows it to have good compatibility with polylactic acid. With a 5% addition, it can be uniformly dispersed in the polylactic acid matrix instead of the microphase region. , to minimize its impact on the transparency of the matrix. From the experimental results (Figure 2), although the melt strength provided by BPMS-255 is inferior to BPMS-265, its effect on product transparency, mainly turbidity, is very small and almost negligible, while BPMS -265 has a certain effect on the turbidity of the product. Manufacturers can choose more suitable brands according to their own requirements for products.
PARALOIDTM BPMS series processing aids in the polylactic acid system excellent performance to make polylactic acid processing easier. With the introduction of impact modifiers (BPM Series) and processing aids (BPMS Series) for polylactic acid systems, as an environmentally friendly degradable material, the field of application of polylactic acid is continuously expanding. It is a good thing for the entire chemical industry and even the sustainable development of society. Rohm and Haas Company, as a member of the chemical industry, will continue to strengthen research with its own sense of responsibility for the future and strive to develop more functional products to meet a wider range of requirements. It can be represented by polylactic acid. The promotion and application of degradable plastics contribute their own strength. Degradable plastic instead of traditional plastic seems to be difficult now, but as Rohm and Haas’s credo “Image the Possibilities” put it, this is a new future with unlimited possibilities.

Figure 1. Increase in Melt Strength of Polylactic Acid System with PARALOIDTM BPMS Series

Figure 2. Effect of PARALOIDTM BPMS series on turbidity of polylactic acid system