The Research On Transparent Toughening Modification Of Polypropylene Plastic Woven Bag

As a general-purpose material,polypropylene(PP)is widely used because of its low cost and easy preparation.However,its impact strength is poor,dimensional stability is not good,and transparency is not high.In this paper,sorbitol nucleating agent(WBQ-88A)and metallocene polypropylene(mPP)were used as modifiers to prepare composite packaging film by melt blending extrusion granulation and blown film.The transparency is improved mainly by increasing the crystallinity of the polypropylene,so that the particles are uniformly distributed,and the toughness is improved mainly by changing the structure of the polypropylene,so that the added modifier and the polypropylene form a "sea-island"structure.First,the ratio of the transparent nucleating agent to the polypropylene is changed,and at the same time,an antioxidant,a stabilizer,and a dispersing agent are added to prepare a film.The mass fraction of the nucleating agent was 0.1%,0.2%,0.25%,0.3%,and 0.4%,respectively.The test was carried out by a polarizing microscope,a wide-angle X-ray diffraction,a DSC test,a light transmission/haze meter,an impact strength,and a tensile strength.The results show that when the content of transparent nucleating agent is 0.25%,the crystallinity is high,the transparency is the best,reaching 90.5%,and the tensile strength and elongation at break are increased to 28.53MPa and 205.66%,respectively,reaching the highest level.The impact performance is reduced.The toughness was changed by adding metallocene polypropylene alone,and the mass fractions were 10%,12%,14%,16%,and 18%,respectively.As the content of metallocene polypropylene modifier increases,the impact strength of the sample increases gradually.When the metallocene polypropylene content is 16%,the impact strength is the highest,reaching 41.14 KJ/m2.Since the metallocene polypropylene has a narrow molecular weight distribution,good transparency and toughness,and good compatibility with polypropylene,as the content of the metallocene polypropylene increases,the transparency of the sample gradually increases,and then tends to be stable.When the metallocene polypropylene content is 16%,the tensile strength and elongation at break are increased to 44.73MPa and 675.97%,respectively.Finally,the transparent nucleating agent and the metallocene polypropylene are mixed together to modify the polypropylene to maintain the transparent nucleating agent content at 0.25%,and gradually add metallocene polypropylene with mass fraction of 10%,12%,14%,16%,and 18%.Through various performance tests,it was found that when the mass fraction of nucleating agent was 0.25%and the mass fraction of metallocene polypropylene was 16%,the transparency and toughness modification effect is best,the transparency reached 90.6%,the impact strength reached 29.14MPa,the tensile strength and elongation at break were 31.14MPa and 506.52%,respectively.